We've had some problems with request corruption on IDE in the past, IBM
traced these to stack corruption. In various places, the IDE code does
something ala:
submission:
struct request rq;
...
ide_do_drive_cmd(drive, &rq, ide_wait);
ide_end_request:
...
blkdev_release_request()
which works fine, as long as the stack persists for the
blkdev_release_request() call, but it may not if the task has already
exited (CPU0 may be waiting in ide_do_drive_cmd(), CPU1 gets the
completion interrupt, task is woken, and exits, CPU0 now calls
blkdev_release_request()). The result is random stack corruption (or
request list corruption, rq->q may have been scrippled!), not good.
The solution is to allocate the requests from the ordinary block pool,
which not alone fixes the problem but also is a lot cleaner IMHO. I've
added blk_get_request() which is identical to what I added in 2.5, so we
can easily carry this fix forward to the 2.5 IDE base as well.
diff -ur -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.4.21-pre7/drivers/block/ll_rw_blk.c linux-2.4.21-pre7/drivers/block/ll_rw_blk.c
--- /opt/kernel/linux-2.4.21-pre7/drivers/block/ll_rw_blk.c 2003-04-14 10:48:21.000000000 +0200
+++ linux-2.4.21-pre7/drivers/block/ll_rw_blk.c 2003-04-14 11:28:51.000000000 +0200
@@ -427,7 +427,9 @@
INIT_LIST_HEAD(&q->rq[READ].free);
INIT_LIST_HEAD(&q->rq[WRITE].free);
q->rq[READ].count = 0;
+ q->rq[READ].wait = &q->wait_for_requests[READ];
q->rq[WRITE].count = 0;
+ q->rq[WRITE].wait = &q->wait_for_requests[WRITE];
q->nr_requests = 0;
si_meminfo(&si);
@@ -521,6 +523,7 @@
rq->cmd = rw;
rq->special = NULL;
rq->q = q;
+ rq->rl = rl;
}
return rq;
@@ -605,6 +608,30 @@
return rq;
}
+struct request *blk_get_request(request_queue_t *q, int rw, int gfp_mask)
+{
+ struct request *rq;
+ unsigned long flags;
+
+ BUG_ON(rw != READ && rw != WRITE);
+
+ spin_lock_irqsave(&io_request_lock, flags);
+ rq = get_request(q, rw);
+ spin_unlock_irqrestore(&io_request_lock, flags);
+
+ if (!rq && (gfp_mask & __GFP_WAIT))
+ rq = __get_request_wait(q, rw);
+
+ if (rq) {
+ rq->buffer = NULL;
+ rq->bh = rq->bhtail = NULL;
+ rq->waiting = NULL;
+ rq->special = NULL;
+ }
+
+ return rq;
+}
+
/* RO fail safe mechanism */
static long ro_bits[MAX_BLKDEV][8];
@@ -818,20 +845,21 @@
void blkdev_release_request(struct request *req)
{
request_queue_t *q = req->q;
- int rw = req->cmd;
+ struct request_list *rl = req->rl;
req->rq_status = RQ_INACTIVE;
req->q = NULL;
+ req->rl = NULL;
/*
* Request may not have originated from ll_rw_blk. if not,
* assume it has free buffers and check waiters
*/
- if (q) {
- list_add(&req->queue, &q->rq[rw].free);
- if (++q->rq[rw].count >= q->batch_requests &&
- waitqueue_active(&q->wait_for_requests[rw]))
- wake_up(&q->wait_for_requests[rw]);
+ if (rl) {
+ list_add(&req->queue, &rl->free);
+ if (++rl->count >= q->batch_requests &&
+ waitqueue_active(rl->wait))
+ wake_up(rl->wait);
}
}
@@ -1518,3 +1546,4 @@
EXPORT_SYMBOL(blk_max_pfn);
EXPORT_SYMBOL(blk_seg_merge_ok);
EXPORT_SYMBOL(blk_nohighio);
+EXPORT_SYMBOL(blk_get_request);
diff -ur -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.4.21-pre7/drivers/ide/ide-cd.c linux-2.4.21-pre7/drivers/ide/ide-cd.c
--- /opt/kernel/linux-2.4.21-pre7/drivers/ide/ide-cd.c 2003-04-14 10:48:22.000000000 +0200
+++ linux-2.4.21-pre7/drivers/ide/ide-cd.c 2003-04-14 11:13:38.000000000 +0200
@@ -1601,7 +1601,7 @@
int cdrom_queue_packet_command(ide_drive_t *drive, struct packet_command *pc)
{
struct request_sense sense;
- struct request req;
+ struct request *req;
int retries = 10;
if (pc->sense == NULL)
@@ -1609,10 +1609,11 @@
/* Start of retry loop. */
do {
- ide_init_drive_cmd (&req);
- req.cmd = PACKET_COMMAND;
- req.buffer = (char *)pc;
- ide_do_drive_cmd(drive, &req, ide_wait);
+ req = blk_get_request(&drive->queue, WRITE, GFP_KERNEL);
+ ide_init_drive_cmd (req);
+ req->cmd = PACKET_COMMAND;
+ req->buffer = (char *)pc;
+ ide_do_drive_cmd(drive, req, ide_wait);
/* FIXME: we should probably abort/retry or something
* in case of failure */
if (pc->stat != 0) {
@@ -2487,12 +2488,12 @@
{
ide_drive_t *drive = (ide_drive_t*) cdi->handle;
struct request_sense sense;
- struct request req;
+ struct request *req = blk_get_request(&drive->queue, WRITE, GFP_KERNEL);
int ret;
- ide_init_drive_cmd (&req);
- req.cmd = RESET_DRIVE_COMMAND;
- ret = ide_do_drive_cmd(drive, &req, ide_wait);
+ ide_init_drive_cmd (req);
+ req->cmd = RESET_DRIVE_COMMAND;
+ ret = ide_do_drive_cmd(drive, req, ide_wait);
/*
* A reset will unlock the door. If it was previously locked,
diff -ur -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.4.21-pre7/drivers/ide/ide-disk.c linux-2.4.21-pre7/drivers/ide/ide-disk.c
--- /opt/kernel/linux-2.4.21-pre7/drivers/ide/ide-disk.c 2003-04-14 10:48:22.000000000 +0200
+++ linux-2.4.21-pre7/drivers/ide/ide-disk.c 2003-04-14 11:07:24.000000000 +0200
@@ -1414,15 +1414,16 @@
*/
static int set_multcount(ide_drive_t *drive, int arg)
{
- struct request rq;
+ struct request *rq;
if (drive->special.b.set_multmode)
return -EBUSY;
- ide_init_drive_cmd (&rq);
- rq.cmd = IDE_DRIVE_CMD;
+ rq = blk_get_request(&drive->queue, WRITE, GFP_KERNEL);
+ ide_init_drive_cmd (rq);
+ rq->cmd = IDE_DRIVE_CMD;
drive->mult_req = arg;
drive->special.b.set_multmode = 1;
- (void) ide_do_drive_cmd (drive, &rq, ide_wait);
+ (void) ide_do_drive_cmd (drive, rq, ide_wait);
return (drive->mult_count == arg) ? 0 : -EIO;
}
diff -ur -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.4.21-pre7/drivers/ide/ide-io.c linux-2.4.21-pre7/drivers/ide/ide-io.c
--- /opt/kernel/linux-2.4.21-pre7/drivers/ide/ide-io.c 2003-04-14 10:48:22.000000000 +0200
+++ linux-2.4.21-pre7/drivers/ide/ide-io.c 2003-04-14 10:53:01.000000000 +0200
@@ -1281,8 +1281,10 @@
void ide_init_drive_cmd (struct request *rq)
{
- memset(rq, 0, sizeof(*rq));
+ INIT_LIST_HEAD(&rq->queue);
rq->cmd = IDE_DRIVE_CMD;
+ rq->special = rq->buffer = NULL;
+ rq->bh = rq->bhtail = NULL;
}
EXPORT_SYMBOL(ide_init_drive_cmd);
diff -ur -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.4.21-pre7/drivers/ide/ide-taskfile.c linux-2.4.21-pre7/drivers/ide/ide-taskfile.c
--- /opt/kernel/linux-2.4.21-pre7/drivers/ide/ide-taskfile.c 2003-04-14 10:48:22.000000000 +0200
+++ linux-2.4.21-pre7/drivers/ide/ide-taskfile.c 2003-04-14 11:16:15.000000000 +0200
@@ -1306,7 +1306,7 @@
*/
void ide_init_drive_taskfile (struct request *rq)
{
- memset(rq, 0, sizeof(*rq));
+ ide_init_drive_cmd(rq);
rq->cmd = IDE_DRIVE_TASK_NO_DATA;
}
@@ -1316,11 +1316,11 @@
int ide_diag_taskfile (ide_drive_t *drive, ide_task_t *args, unsigned long data_size, u8 *buf)
{
- struct request rq;
+ struct request *rq = blk_get_request(&drive->queue, WRITE, GFP_KERNEL);
- ide_init_drive_taskfile(&rq);
- rq.cmd = IDE_DRIVE_TASKFILE;
- rq.buffer = buf;
+ ide_init_drive_taskfile(rq);
+ rq->cmd = IDE_DRIVE_TASKFILE;
+ rq->buffer = buf;
/*
* (ks) We transfer currently only whole sectors.
@@ -1330,11 +1330,11 @@
*/
if (args->command_type != IDE_DRIVE_TASK_NO_DATA) {
if (data_size == 0)
- rq.current_nr_sectors = rq.nr_sectors = (args->hobRegister[IDE_NSECTOR_OFFSET_HOB] << 8) | args->tfRegister[IDE_NSECTOR_OFFSET];
- /* rq.hard_cur_sectors */
+ rq->current_nr_sectors = rq->nr_sectors = (args->hobRegister[IDE_NSECTOR_OFFSET_HOB] << 8) | args->tfRegister[IDE_NSECTOR_OFFSET];
+ /* rq->hard_cur_sectors */
else
- rq.current_nr_sectors = rq.nr_sectors = data_size / SECTOR_SIZE;
- /* rq.hard_cur_sectors */
+ rq->current_nr_sectors = rq->nr_sectors = data_size / SECTOR_SIZE;
+ /* rq->hard_cur_sectors */
}
if (args->tf_out_flags.all == 0) {
@@ -1347,8 +1347,8 @@
(struct hd_drive_hob_hdr *) args->hobRegister);
}
- rq.special = args;
- return ide_do_drive_cmd(drive, &rq, ide_wait);
+ rq->special = args;
+ return ide_do_drive_cmd(drive, rq, ide_wait);
}
#else
@@ -1649,19 +1649,19 @@
int ide_wait_cmd (ide_drive_t *drive, u8 cmd, u8 nsect, u8 feature, u8 sectors, u8 *buf)
{
- struct request rq;
+ struct request *rq = blk_get_request(&drive->queue, WRITE, GFP_KERNEL);
u8 buffer[4];
if (!buf)
buf = buffer;
memset(buf, 0, 4 + SECTOR_WORDS * 4 * sectors);
- ide_init_drive_cmd(&rq);
- rq.buffer = buf;
+ ide_init_drive_cmd(rq);
+ rq->buffer = buf;
*buf++ = cmd;
*buf++ = nsect;
*buf++ = feature;
*buf++ = sectors;
- return ide_do_drive_cmd(drive, &rq, ide_wait);
+ return ide_do_drive_cmd(drive, rq, ide_wait);
}
EXPORT_SYMBOL(ide_wait_cmd);
@@ -1679,9 +1679,9 @@
ide_task_t tfargs;
if (NULL == (void *) arg) {
- struct request rq;
- ide_init_drive_cmd(&rq);
- return ide_do_drive_cmd(drive, &rq, ide_wait);
+ struct request *rq = blk_get_request(&drive->queue, WRITE, GFP_KERNEL);
+ ide_init_drive_cmd(rq);
+ return ide_do_drive_cmd(drive, rq, ide_wait);
}
if (copy_from_user(args, (void *)arg, 4))
@@ -1732,9 +1732,9 @@
ide_task_t tfargs;
if (NULL == (void *) arg) {
- struct request rq;
- ide_init_drive_cmd(&rq);
- return ide_do_drive_cmd(drive, &rq, ide_wait);
+ struct request *rq = blk_get_request(&drive->queue, WRITE, GFP_KERNEL);
+ ide_init_drive_cmd(rq);
+ return ide_do_drive_cmd(drive, rq, ide_wait);
}
if (copy_from_user(args, (void *)arg, 4))
@@ -1792,12 +1792,12 @@
int ide_wait_cmd_task (ide_drive_t *drive, u8 *buf)
{
- struct request rq;
+ struct request *rq = blk_get_request(&drive->queue, WRITE, GFP_KERNEL);
- ide_init_drive_cmd(&rq);
- rq.cmd = IDE_DRIVE_TASK;
- rq.buffer = buf;
- return ide_do_drive_cmd(drive, &rq, ide_wait);
+ ide_init_drive_cmd(rq);
+ rq->cmd = IDE_DRIVE_TASK;
+ rq->buffer = buf;
+ return ide_do_drive_cmd(drive, rq, ide_wait);
}
EXPORT_SYMBOL(ide_wait_cmd_task);
diff -ur -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.4.21-pre7/drivers/ide/ide.c linux-2.4.21-pre7/drivers/ide/ide.c
--- /opt/kernel/linux-2.4.21-pre7/drivers/ide/ide.c 2003-04-14 10:48:22.000000000 +0200
+++ linux-2.4.21-pre7/drivers/ide/ide.c 2003-04-14 11:08:25.000000000 +0200
@@ -1359,16 +1359,17 @@
static int set_pio_mode (ide_drive_t *drive, int arg)
{
- struct request rq;
+ struct request *rq;
if (!HWIF(drive)->tuneproc)
return -ENOSYS;
if (drive->special.b.set_tune)
return -EBUSY;
- ide_init_drive_cmd(&rq);
+ rq = blk_get_request(&drive->queue, WRITE, GFP_KERNEL);
+ ide_init_drive_cmd(rq);
drive->tune_req = (u8) arg;
drive->special.b.set_tune = 1;
- (void) ide_do_drive_cmd(drive, &rq, ide_wait);
+ (void) ide_do_drive_cmd(drive, rq, ide_wait);
return 0;
}
@@ -1533,7 +1534,6 @@
{
int err = 0, major, minor;
ide_drive_t *drive;
- struct request rq;
kdev_t dev;
ide_settings_t *setting;
@@ -1560,7 +1560,6 @@
}
up(&ide_setting_sem);
- ide_init_drive_cmd (&rq);
switch (cmd) {
case HDIO_GETGEO:
{
diff -ur -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.4.21-pre7/include/linux/blkdev.h linux-2.4.21-pre7/include/linux/blkdev.h
--- /opt/kernel/linux-2.4.21-pre7/include/linux/blkdev.h 2003-04-14 10:48:24.000000000 +0200
+++ linux-2.4.21-pre7/include/linux/blkdev.h 2003-04-14 11:26:31.000000000 +0200
@@ -15,6 +15,12 @@
struct elevator_s;
typedef struct elevator_s elevator_t;
+struct request_list {
+ unsigned int count;
+ wait_queue_head_t *wait;
+ struct list_head free;
+};
+
/*
* Ok, this is an expanded form so that we can use the same
* request for paging requests.
@@ -46,6 +52,7 @@
struct buffer_head * bh;
struct buffer_head * bhtail;
request_queue_t *q;
+ struct request_list *rl;
};
#include <linux/elevator.h>
@@ -70,11 +77,6 @@
*/
#define QUEUE_NR_REQUESTS 8192
-struct request_list {
- unsigned int count;
- struct list_head free;
-};
-
struct request_queue
{
/*
@@ -217,6 +219,7 @@
extern void generic_make_request(int rw, struct buffer_head * bh);
extern inline request_queue_t *blk_get_queue(kdev_t dev);
extern void blkdev_release_request(struct request *);
+extern struct request *blk_get_request(request_queue_t *, int, int);
/*
* Access functions for manipulating queue properties
-- Jens Axboe- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/