minix/servers/vfs/device.c
Lionel Sambuc 37598dccf1 Aligning dev_t to 64bits.
Change-Id: I630f72f8530dd4aaf05c35ca23683ae12c9f8328
2014-03-02 12:28:32 +01:00

819 lines
23 KiB
C

/* When a needed block is not in the cache, it must be fetched from the disk.
* Special character files also require I/O. The routines for these are here.
*
* The entry points in this file are:
* cdev_open: open a character device
* cdev_close: close a character device
* cdev_io: initiate a read, write, or ioctl to a character device
* cdev_select: initiate a select call on a device
* cdev_cancel: cancel an I/O request, blocking until it has been cancelled
* cdev_reply: process the result of a character driver request
* bdev_open: open a block device
* bdev_close: close a block device
* bdev_reply: process the result of a block driver request
* bdev_up: a block driver has been mapped in
* do_ioctl: perform the IOCTL system call
*/
#include "fs.h"
#include <string.h>
#include <fcntl.h>
#include <assert.h>
#include <sys/stat.h>
#include <sys/ttycom.h>
#include <minix/callnr.h>
#include <minix/com.h>
#include <minix/endpoint.h>
#include <minix/ioctl.h>
#include <minix/u64.h>
#include "file.h"
#include "scratchpad.h"
#include "dmap.h"
#include <minix/vfsif.h>
#include "vnode.h"
#include "vmnt.h"
static int cdev_opcl(int op, dev_t dev, int flags);
static int block_io(endpoint_t driver_e, message *mess_ptr);
static cp_grant_id_t make_grant(endpoint_t driver_e, endpoint_t user_e, int op,
void *buf, unsigned long size);
/*===========================================================================*
* bdev_open *
*===========================================================================*/
int bdev_open(dev_t dev, int access)
{
/* Open a block device. */
devmajor_t major_dev;
devminor_t minor_dev;
message dev_mess;
int r;
major_dev = major(dev);
minor_dev = minor(dev);
if (major_dev < 0 || major_dev >= NR_DEVICES) return ENXIO;
if (dmap[major_dev].dmap_driver == NONE) return ENXIO;
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = BDEV_OPEN;
dev_mess.BDEV_MINOR = minor_dev;
dev_mess.BDEV_ACCESS = 0;
if (access & R_BIT) dev_mess.BDEV_ACCESS |= BDEV_R_BIT;
if (access & W_BIT) dev_mess.BDEV_ACCESS |= BDEV_W_BIT;
dev_mess.BDEV_ID = 0;
/* Call the task. */
r = block_io(dmap[major_dev].dmap_driver, &dev_mess);
if (r != OK)
return r;
return dev_mess.BDEV_STATUS;
}
/*===========================================================================*
* bdev_close *
*===========================================================================*/
int bdev_close(dev_t dev)
{
/* Close a block device. */
devmajor_t major_dev;
devminor_t minor_dev;
message dev_mess;
int r;
major_dev = major(dev);
minor_dev = minor(dev);
if (major_dev < 0 || major_dev >= NR_DEVICES) return ENXIO;
if (dmap[major_dev].dmap_driver == NONE) return ENXIO;
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = BDEV_CLOSE;
dev_mess.BDEV_MINOR = minor_dev;
dev_mess.BDEV_ID = 0;
r = block_io(dmap[major_dev].dmap_driver, &dev_mess);
if (r != OK)
return r;
return dev_mess.BDEV_STATUS;
}
/*===========================================================================*
* bdev_ioctl *
*===========================================================================*/
static int bdev_ioctl(dev_t dev, endpoint_t proc_e, unsigned long req,
void *buf)
{
/* Perform an I/O control operation on a block device. */
struct dmap *dp;
cp_grant_id_t gid;
message dev_mess;
devmajor_t major_dev;
devminor_t minor_dev;
int r;
major_dev = major(dev);
minor_dev = minor(dev);
/* Determine task dmap. */
dp = &dmap[major_dev];
if (dp->dmap_driver == NONE) {
printf("VFS: bdev_ioctl: no driver for major %d\n", major_dev);
return(ENXIO);
}
/* Set up a grant if necessary. */
gid = make_grant(dp->dmap_driver, proc_e, BDEV_IOCTL, buf, req);
/* Set up the message passed to the task. */
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = BDEV_IOCTL;
dev_mess.BDEV_MINOR = minor_dev;
dev_mess.BDEV_REQUEST = req;
dev_mess.BDEV_GRANT = gid;
dev_mess.BDEV_USER = proc_e;
dev_mess.BDEV_ID = 0;
/* Call the task. */
r = block_io(dp->dmap_driver, &dev_mess);
/* Clean up. */
if (GRANT_VALID(gid)) cpf_revoke(gid);
/* Return the result. */
if (r != OK)
return(r);
return(dev_mess.BDEV_STATUS);
}
/*===========================================================================*
* make_grant *
*===========================================================================*/
static cp_grant_id_t make_grant(endpoint_t driver_e, endpoint_t user_e, int op,
void *buf, unsigned long bytes)
{
/* Create a magic grant for the given operation and buffer. */
cp_grant_id_t gid;
int access;
size_t size;
switch (op) {
case CDEV_READ:
case CDEV_WRITE:
gid = cpf_grant_magic(driver_e, user_e, (vir_bytes) buf,
(size_t) bytes, op == CDEV_READ ? CPF_WRITE : CPF_READ);
break;
case CDEV_IOCTL:
case BDEV_IOCTL:
/* For IOCTLs, the bytes parameter contains the IOCTL request.
* This request encodes the requested access method and buffer size.
*/
access = 0;
if(_MINIX_IOCTL_IOR(bytes)) access |= CPF_WRITE;
if(_MINIX_IOCTL_IOW(bytes)) access |= CPF_READ;
if(_MINIX_IOCTL_BIG(bytes))
size = _MINIX_IOCTL_SIZE_BIG(bytes);
else
size = _MINIX_IOCTL_SIZE(bytes);
/* Grant access to the buffer even if no I/O happens with the ioctl,
* although now that we no longer identify responses based on grants,
* this is not strictly necessary.
*/
gid = cpf_grant_magic(driver_e, user_e, (vir_bytes) buf, size, access);
break;
default:
panic("VFS: unknown operation %d", op);
}
if (!GRANT_VALID(gid))
panic("VFS: cpf_grant_magic failed");
return gid;
}
/*===========================================================================*
* cdev_get *
*===========================================================================*/
static struct dmap *cdev_get(dev_t dev, devminor_t *minor_dev)
{
/* Obtain the dmap structure for the given device, if a valid driver exists for
* the major device. Perform redirection for CTTY_MAJOR.
*/
devmajor_t major_dev;
struct dmap *dp;
int slot;
/* First cover one special case: /dev/tty, the magic device that translates
* to the controlling tty.
*/
if (major(dev) == CTTY_MAJOR) {
/* No controlling terminal? Fail the request. */
if (fp->fp_tty == 0) return(NULL);
/* Substitute the controlling terminal device. */
dev = fp->fp_tty;
}
/* Determine task dmap. */
major_dev = major(dev);
if (major_dev < 0 || major_dev >= NR_DEVICES) return(NULL);
dp = &dmap[major_dev];
/* See if driver is roughly valid. */
if (dp->dmap_driver == NONE) return(NULL);
if (isokendpt(dp->dmap_driver, &slot) != OK) {
printf("VFS: cdev_get: old driver for major %x (%d)\n", major_dev,
dp->dmap_driver);
return(NULL);
}
/* Also return the (possibly redirected) minor number. */
*minor_dev = minor(dev);
return dp;
}
/*===========================================================================*
* cdev_io *
*===========================================================================*/
int cdev_io(
int op, /* CDEV_READ, CDEV_WRITE, or CDEV_IOCTL */
dev_t dev, /* major-minor device number */
endpoint_t proc_e, /* in whose address space is buf? */
void *buf, /* virtual address of the buffer */
off_t pos, /* byte position */
unsigned long bytes, /* how many bytes to transfer, or request */
int flags /* special flags, like O_NONBLOCK */
)
{
/* Initiate a read, write, or ioctl to a character device. */
devminor_t minor_dev;
struct dmap *dp;
message dev_mess;
cp_grant_id_t gid;
int r;
assert(op == CDEV_READ || op == CDEV_WRITE || op == CDEV_IOCTL);
/* Determine task map. */
if ((dp = cdev_get(dev, &minor_dev)) == NULL)
return(EIO);
/* Handle TIOCSCTTY ioctl: set controlling tty.
* TODO: cleaner implementation work in progress.
*/
if (op == CDEV_IOCTL && bytes == TIOCSCTTY && major(dev) == TTY_MAJOR) {
fp->fp_tty = dev;
}
/* Create a grant for the buffer provided by the user process. */
gid = make_grant(dp->dmap_driver, proc_e, op, buf, bytes);
/* Set up the rest of the message that will be sent to the driver. */
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = op;
dev_mess.CDEV_MINOR = minor_dev;
if (op == CDEV_IOCTL) {
dev_mess.CDEV_REQUEST = bytes;
dev_mess.CDEV_USER = proc_e;
} else {
dev_mess.CDEV_POS_LO = ex64lo(pos);
dev_mess.CDEV_POS_HI = ex64hi(pos);
dev_mess.CDEV_COUNT = (size_t) bytes;
}
dev_mess.CDEV_ID = proc_e;
dev_mess.CDEV_GRANT = gid;
dev_mess.CDEV_FLAGS = 0;
if (flags & O_NONBLOCK)
dev_mess.CDEV_FLAGS |= CDEV_NONBLOCK;
/* Send the request to the driver. */
if ((r = asynsend3(dp->dmap_driver, &dev_mess, AMF_NOREPLY)) != OK)
panic("VFS: asynsend in cdev_io failed: %d", r);
/* Suspend the calling process until a reply arrives. */
wait_for(dp->dmap_driver);
assert(!GRANT_VALID(fp->fp_grant));
fp->fp_grant = gid; /* revoke this when unsuspended. */
return SUSPEND;
}
/*===========================================================================*
* cdev_clone *
*===========================================================================*/
static int cdev_clone(dev_t dev, devminor_t new_minor)
{
/* A new minor device number has been returned. Request PFS to create a
* temporary device file to hold it.
*/
struct vnode *vp;
struct node_details res;
int r;
/* Device number of the new device. */
dev = makedev(major(dev), new_minor);
/* Issue request */
r = req_newnode(PFS_PROC_NR, fp->fp_effuid, fp->fp_effgid,
ALL_MODES | I_CHAR_SPECIAL, dev, &res);
if (r != OK) {
(void) cdev_opcl(CDEV_CLOSE, dev, 0);
return r;
}
/* Drop old node and use the new values */
if ((vp = get_free_vnode()) == NULL) {
req_putnode(PFS_PROC_NR, res.inode_nr, 1); /* is this right? */
(void) cdev_opcl(CDEV_CLOSE, dev, 0);
return(err_code);
}
lock_vnode(vp, VNODE_OPCL);
assert(fp->fp_filp[scratch(fp).file.fd_nr] != NULL);
unlock_vnode(fp->fp_filp[scratch(fp).file.fd_nr]->filp_vno);
put_vnode(fp->fp_filp[scratch(fp).file.fd_nr]->filp_vno);
vp->v_fs_e = res.fs_e;
vp->v_vmnt = NULL;
vp->v_dev = NO_DEV;
vp->v_fs_e = res.fs_e;
vp->v_inode_nr = res.inode_nr;
vp->v_mode = res.fmode;
vp->v_sdev = dev;
vp->v_fs_count = 1;
vp->v_ref_count = 1;
fp->fp_filp[scratch(fp).file.fd_nr]->filp_vno = vp;
return OK;
}
/*===========================================================================*
* cdev_opcl *
*===========================================================================*/
static int cdev_opcl(
int op, /* operation, CDEV_OPEN or CDEV_CLOSE */
dev_t dev, /* device to open or close */
int flags /* mode bits and flags */
)
{
/* Open or close a character device. */
devminor_t minor_dev, new_minor;
struct dmap *dp;
struct fproc *rfp;
message dev_mess;
int r, r2;
assert(op == CDEV_OPEN || op == CDEV_CLOSE);
/* Determine task dmap. */
if ((dp = cdev_get(dev, &minor_dev)) == NULL)
return(ENXIO);
/* CTTY exception: do not actually send the open/close request for /dev/tty
* to the driver. This avoids the case that the actual device will remain
* open forever if the process calls setsid() after opening /dev/tty.
*/
if (major(dev) == CTTY_MAJOR) return(OK);
/* Add O_NOCTTY to the access flags if this process is not a session leader,
* or if it already has a controlling tty, or if it is someone else's
* controlling tty. For performance reasons, only search the full process
* table if this driver has set controlling ttys before.
*/
if (!(fp->fp_flags & FP_SESLDR) || fp->fp_tty != 0) {
flags |= O_NOCTTY;
} else if (!(flags & O_NOCTTY) && dp->dmap_seen_tty) {
for (rfp = &fproc[0]; rfp < &fproc[NR_PROCS]; rfp++)
if (rfp->fp_pid != PID_FREE && rfp->fp_tty == dev)
flags |= O_NOCTTY;
}
/* Prepare the request message. */
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = op;
dev_mess.CDEV_MINOR = minor_dev;
dev_mess.CDEV_ID = who_e;
if (op == CDEV_OPEN) {
dev_mess.CDEV_USER = who_e;
dev_mess.CDEV_ACCESS = 0;
if (flags & R_BIT) dev_mess.CDEV_ACCESS |= CDEV_R_BIT;
if (flags & W_BIT) dev_mess.CDEV_ACCESS |= CDEV_W_BIT;
if (flags & O_NOCTTY) dev_mess.CDEV_ACCESS |= CDEV_NOCTTY;
}
/* Send the request to the driver. */
if ((r = asynsend3(dp->dmap_driver, &dev_mess, AMF_NOREPLY)) != OK)
panic("VFS: asynsend in cdev_opcl failed: %d", r);
/* Block the thread waiting for a reply. */
fp->fp_task = dp->dmap_driver;
self->w_task = dp->dmap_driver;
self->w_drv_sendrec = &dev_mess;
worker_wait();
self->w_task = NONE;
self->w_drv_sendrec = NULL;
/* Process the reply. */
r = dev_mess.CDEV_STATUS;
if (op == CDEV_OPEN && r >= 0) {
/* Some devices need special processing upon open. Such a device is
* "cloned", i.e. on a succesful open it is replaced by a new device
* with a new unique minor device number. This new device number
* identifies a new object (such as a new network connection) that has
* been allocated within a driver.
*/
if (r & CDEV_CLONED) {
new_minor = r & ~(CDEV_CLONED | CDEV_CTTY);
if ((r2 = cdev_clone(dev, new_minor)) < 0)
return(r2);
}
/* Did this call make the tty the controlling tty? */
if (r & CDEV_CTTY) {
fp->fp_tty = dev;
dp->dmap_seen_tty = TRUE;
}
r = OK;
}
/* Return the result from the driver. */
return(r);
}
/*===========================================================================*
* cdev_open *
*===========================================================================*/
int cdev_open(dev_t dev, int flags)
{
/* Open a character device. */
return cdev_opcl(CDEV_OPEN, dev, flags);
}
/*===========================================================================*
* cdev_close *
*===========================================================================*/
int cdev_close(dev_t dev)
{
/* Close a character device. */
return cdev_opcl(CDEV_CLOSE, dev, 0);
}
/*===========================================================================*
* do_ioctl *
*===========================================================================*/
int do_ioctl(void)
{
/* Perform the ioctl(2) system call. */
unsigned long ioctlrequest;
int r = OK;
struct filp *f;
register struct vnode *vp;
dev_t dev;
void *argx;
scratch(fp).file.fd_nr = job_m_in.VFS_IOCTL_FD;
ioctlrequest = job_m_in.VFS_IOCTL_REQ;
argx = job_m_in.VFS_IOCTL_ARG;
if ((f = get_filp(scratch(fp).file.fd_nr, VNODE_READ)) == NULL)
return(err_code);
vp = f->filp_vno; /* get vnode pointer */
if (!S_ISCHR(vp->v_mode) && !S_ISBLK(vp->v_mode)) {
r = ENOTTY;
}
if (r == OK) {
dev = vp->v_sdev;
if (S_ISBLK(vp->v_mode)) {
f->filp_ioctl_fp = fp;
r = bdev_ioctl(dev, who_e, ioctlrequest, argx);
f->filp_ioctl_fp = NULL;
} else
r = cdev_io(CDEV_IOCTL, dev, who_e, argx, 0, ioctlrequest,
f->filp_flags);
}
unlock_filp(f);
return(r);
}
/*===========================================================================*
* cdev_select *
*===========================================================================*/
int cdev_select(dev_t dev, int ops)
{
/* Initiate a select call on a device. Return OK iff the request was sent. */
devminor_t minor_dev;
message dev_mess;
struct dmap *dp;
int r;
/* Determine task dmap. */
if ((dp = cdev_get(dev, &minor_dev)) == NULL)
return(EIO);
/* Prepare the request message. */
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = CDEV_SELECT;
dev_mess.CDEV_MINOR = minor_dev;
dev_mess.CDEV_OPS = ops;
/* Send the request to the driver. */
if ((r = asynsend3(dp->dmap_driver, &dev_mess, AMF_NOREPLY)) != OK)
panic("VFS: asynsend in cdev_select failed: %d", r);
return(OK);
}
/*===========================================================================*
* cdev_cancel *
*===========================================================================*/
int cdev_cancel(dev_t dev)
{
/* Cancel an I/O request, blocking until it has been cancelled. */
devminor_t minor_dev;
message dev_mess;
struct dmap *dp;
int r;
/* Determine task dmap. */
if ((dp = cdev_get(dev, &minor_dev)) == NULL)
return(EIO);
/* Prepare the request message. */
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = CDEV_CANCEL;
dev_mess.CDEV_MINOR = minor_dev;
dev_mess.CDEV_ID = fp->fp_endpoint;
/* Send the request to the driver. */
if ((r = asynsend3(dp->dmap_driver, &dev_mess, AMF_NOREPLY)) != OK)
panic("VFS: asynsend in cdev_cancel failed: %d", r);
/* Suspend this thread until we have received the response. */
fp->fp_task = dp->dmap_driver;
self->w_task = dp->dmap_driver;
self->w_drv_sendrec = &dev_mess;
worker_wait();
self->w_task = NONE;
self->w_drv_sendrec = NULL;
/* Clean up and return the result (note: the request may have completed). */
if (GRANT_VALID(fp->fp_grant)) {
(void) cpf_revoke(fp->fp_grant);
fp->fp_grant = GRANT_INVALID;
}
r = dev_mess.CDEV_STATUS;
return (r == EAGAIN) ? EINTR : r;
}
/*===========================================================================*
* block_io *
*===========================================================================*/
static int block_io(endpoint_t driver_e, message *mess_ptr)
{
/* Perform I/O on a block device. The current thread is suspended until a reply
* comes in from the driver.
*/
int r, status, retry_count;
message mess_retry;
assert(IS_BDEV_RQ(mess_ptr->m_type));
mess_retry = *mess_ptr;
retry_count = 0;
do {
r = drv_sendrec(driver_e, mess_ptr);
if (r != OK)
return r;
status = mess_ptr->BDEV_STATUS;
if (status == ERESTART) {
r = EDEADEPT;
*mess_ptr = mess_retry;
retry_count++;
}
} while (status == ERESTART && retry_count < 5);
/* If we failed to restart the request, return EIO */
if (status == ERESTART && retry_count >= 5)
return EIO;
if (r != OK) {
if (r == EDEADSRCDST || r == EDEADEPT) {
printf("VFS: dead driver %d\n", driver_e);
dmap_unmap_by_endpt(driver_e);
return(EIO);
} else if (r == ELOCKED) {
printf("VFS: ELOCKED talking to %d\n", driver_e);
return(EIO);
}
panic("block_io: can't send/receive: %d", r);
}
return(OK);
}
/*===========================================================================*
* bdev_up *
*===========================================================================*/
void bdev_up(devmajor_t maj)
{
/* A new block device driver has been mapped in. This may affect both mounted
* file systems and open block-special files.
*/
int r, found, bits;
struct filp *rfilp;
struct vmnt *vmp;
struct vnode *vp;
char *label;
if (maj < 0 || maj >= NR_DEVICES) panic("VFS: out-of-bound major");
label = dmap[maj].dmap_label;
found = 0;
/* For each block-special file that was previously opened on the affected
* device, we need to reopen it on the new driver.
*/
for (rfilp = filp; rfilp < &filp[NR_FILPS]; rfilp++) {
if (rfilp->filp_count < 1 || !(vp = rfilp->filp_vno)) continue;
if (major(vp->v_sdev) != maj) continue;
if (!S_ISBLK(vp->v_mode)) continue;
/* Reopen the device on the driver, once per filp. */
bits = rfilp->filp_mode & (R_BIT|W_BIT);
if ((r = bdev_open(vp->v_sdev, bits)) != OK) {
printf("VFS: mounted dev %d/%d re-open failed: %d.\n",
maj, minor(vp->v_sdev), r);
dmap[maj].dmap_recovering = 0;
return; /* Give up entirely */
}
found = 1;
}
/* Tell each affected mounted file system about the new endpoint.
*/
for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; ++vmp) {
if (major(vmp->m_dev) != maj) continue;
/* Send the driver label to the mounted file system. */
if (OK != req_newdriver(vmp->m_fs_e, vmp->m_dev, label))
printf("VFS dev_up: error sending new driver label to %d\n",
vmp->m_fs_e);
}
/* If any block-special file was open for this major at all, also inform the
* root file system about the new driver. We do this even if the
* block-special file is linked to another mounted file system, merely
* because it is more work to check for that case.
*/
if (found) {
if (OK != req_newdriver(ROOT_FS_E, makedev(maj, 0), label))
printf("VFSdev_up: error sending new driver label to %d\n",
ROOT_FS_E);
}
}
/*===========================================================================*
* cdev_generic_reply *
*===========================================================================*/
static void cdev_generic_reply(message *m_ptr)
{
/* A character driver has results for an open, close, read, write, or ioctl
* call (i.e., everything except select). There may be a thread waiting for
* these results as part of an ongoing open, close, or (for read/write/ioctl)
* cancel call. If so, wake up that thread; if not, send a reply to the
* requesting process. This function MUST NOT block its calling thread.
*/
struct fproc *rfp;
struct worker_thread *wp;
endpoint_t proc_e;
int slot;
proc_e = m_ptr->CDEV_ID;
if (m_ptr->CDEV_STATUS == SUSPEND) {
printf("VFS: got SUSPEND from %d, not reviving\n", m_ptr->m_source);
return;
}
if (isokendpt(proc_e, &slot) != OK) {
printf("VFS: proc %d from %d not found\n", proc_e, m_ptr->m_source);
return;
}
rfp = &fproc[slot];
wp = rfp->fp_worker;
if (wp != NULL && wp->w_task == who_e) {
assert(!fp_is_blocked(rfp));
*wp->w_drv_sendrec = *m_ptr;
worker_signal(wp); /* Continue open/close/cancel */
} else if (rfp->fp_blocked_on != FP_BLOCKED_ON_OTHER ||
rfp->fp_task != m_ptr->m_source) {
/* This would typically be caused by a protocol error, i.e. a driver
* not properly following the character driver protocol rules.
*/
printf("VFS: proc %d not blocked on %d\n", proc_e, m_ptr->m_source);
} else {
revive(proc_e, m_ptr->CDEV_STATUS);
}
}
/*===========================================================================*
* cdev_reply *
*===========================================================================*/
void cdev_reply(void)
{
/* A character driver has results for us. */
if (get_dmap(who_e) == NULL) {
printf("VFS: ignoring char dev reply from unknown driver %d\n", who_e);
return;
}
switch (call_nr) {
case CDEV_REPLY:
cdev_generic_reply(&m_in);
break;
case CDEV_SEL1_REPLY:
select_reply1(m_in.m_source, m_in.CDEV_MINOR, m_in.CDEV_STATUS);
break;
case CDEV_SEL2_REPLY:
select_reply2(m_in.m_source, m_in.CDEV_MINOR, m_in.CDEV_STATUS);
break;
default:
printf("VFS: char driver %u sent unknown reply %x\n", who_e, call_nr);
}
}
/*===========================================================================*
* bdev_reply *
*===========================================================================*/
void bdev_reply(void)
{
/* A block driver has results for a call. There must be a thread waiting for
* these results - wake it up. This function MUST NOT block its calling thread.
*/
struct worker_thread *wp;
struct dmap *dp;
if ((dp = get_dmap(who_e)) == NULL) {
printf("VFS: ignoring block dev reply from unknown driver %d\n",
who_e);
return;
}
if (dp->dmap_servicing == INVALID_THREAD) {
printf("VFS: ignoring spurious block dev reply from %d\n", who_e);
return;
}
wp = worker_get(dp->dmap_servicing);
if (wp == NULL || wp->w_task != who_e) {
printf("VFS: no worker thread waiting for a reply from %d\n", who_e);
return;
}
assert(wp->w_drv_sendrec != NULL);
*wp->w_drv_sendrec = m_in;
wp->w_drv_sendrec = NULL;
worker_signal(wp);
}