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authorIngo Molnar <mingo@elte.hu>2006-07-03 00:24:23 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-07-03 15:27:00 -0700
commit3e541a4ae534a7e59ad464af9abea382b3035724 (patch)
treea3f0de1022e4459d0eadb1f8583956ab7067011a
parent5863aa651bd79a6bb15972894306923db088e71c (diff)
[PATCH] lockdep: floppy.c irq release fix
The lock validator triggered a number of bugs in the floppy driver, all related to the floppy driver allocating and freeing irq and dma resources from interrupt context. The initial solution was to use schedule_work() to push this into process context, but this caused further problems: for example the current floppy driver in -mm2 is totally broken and all floppy commands time out with an error. (as reported by Barry K. Nathan) This patch tries another solution: simply get rid of all that dynamic IRQ and DMA allocation/freeing. I doubt it made much sense back in the heydays of floppies (if two devices raced for DMA or IRQ resources then we didnt handle those cases too gracefully anyway), and today it makes near zero sense. So the new code does the simplest and most straightforward thing: allocate IRQ and DMA resources at module init time, and free them at module removal time. Dont try to release while the driver is operational. This, besides making the floppy driver functional again has an added bonus, floppy IRQ stats are finally persistent and visible in /proc/interrupts: 6: 63 XT-PIC-level floppy Besides normal floppy IO i have also tested IO error handling, motor-off timeouts, etc. - and everything seems to be working fine. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--drivers/block/floppy.c42
1 files changed, 4 insertions, 38 deletions
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 0242cbb86a8..5109fa37c66 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -249,18 +249,6 @@ static int irqdma_allocated;
#include <linux/cdrom.h> /* for the compatibility eject ioctl */
#include <linux/completion.h>
-/*
- * Interrupt freeing also means /proc VFS work - dont do it
- * from interrupt context. We push this work into keventd:
- */
-static void fd_free_irq_fn(void *data)
-{
- fd_free_irq();
-}
-
-static DECLARE_WORK(fd_free_irq_work, fd_free_irq_fn, NULL);
-
-
static struct request *current_req;
static struct request_queue *floppy_queue;
static void do_fd_request(request_queue_t * q);
@@ -826,15 +814,6 @@ static int set_dor(int fdc, char mask, char data)
UDRS->select_date = jiffies;
}
}
- /*
- * We should propagate failures to grab the resources back
- * nicely from here. Actually we ought to rewrite the fd
- * driver some day too.
- */
- if (newdor & FLOPPY_MOTOR_MASK)
- floppy_grab_irq_and_dma();
- if (olddor & FLOPPY_MOTOR_MASK)
- floppy_release_irq_and_dma();
return olddor;
}
@@ -892,8 +871,6 @@ static int _lock_fdc(int drive, int interruptible, int line)
line);
return -1;
}
- if (floppy_grab_irq_and_dma() == -1)
- return -EBUSY;
if (test_and_set_bit(0, &fdc_busy)) {
DECLARE_WAITQUEUE(wait, current);
@@ -915,6 +892,8 @@ static int _lock_fdc(int drive, int interruptible, int line)
set_current_state(TASK_RUNNING);
remove_wait_queue(&fdc_wait, &wait);
+
+ flush_scheduled_work();
}
command_status = FD_COMMAND_NONE;
@@ -948,7 +927,6 @@ static inline void unlock_fdc(void)
if (elv_next_request(floppy_queue))
do_fd_request(floppy_queue);
spin_unlock_irqrestore(&floppy_lock, flags);
- floppy_release_irq_and_dma();
wake_up(&fdc_wait);
}
@@ -3694,8 +3672,8 @@ static int floppy_release(struct inode *inode, struct file *filp)
}
if (!UDRS->fd_ref)
opened_bdev[drive] = NULL;
- floppy_release_irq_and_dma();
mutex_unlock(&open_lock);
+
return 0;
}
@@ -3726,9 +3704,6 @@ static int floppy_open(struct inode *inode, struct file *filp)
if (UDRS->fd_ref == -1 || (UDRS->fd_ref && (filp->f_flags & O_EXCL)))
goto out2;
- if (floppy_grab_irq_and_dma())
- goto out2;
-
if (filp->f_flags & O_EXCL)
UDRS->fd_ref = -1;
else
@@ -3805,7 +3780,6 @@ out:
UDRS->fd_ref--;
if (!UDRS->fd_ref)
opened_bdev[drive] = NULL;
- floppy_release_irq_and_dma();
out2:
mutex_unlock(&open_lock);
return res;
@@ -3822,14 +3796,9 @@ static int check_floppy_change(struct gendisk *disk)
return 1;
if (time_after(jiffies, UDRS->last_checked + UDP->checkfreq)) {
- if (floppy_grab_irq_and_dma()) {
- return 1;
- }
-
lock_fdc(drive, 0);
poll_drive(0, 0);
process_fd_request();
- floppy_release_irq_and_dma();
}
if (UTESTF(FD_DISK_CHANGED) ||
@@ -4346,7 +4315,6 @@ static int __init floppy_init(void)
fdc = 0;
del_timer(&fd_timeout);
current_drive = 0;
- floppy_release_irq_and_dma();
initialising = 0;
if (have_no_fdc) {
DPRINT("no floppy controllers found\n");
@@ -4504,7 +4472,7 @@ static void floppy_release_irq_and_dma(void)
if (irqdma_allocated) {
fd_disable_dma();
fd_free_dma();
- schedule_work(&fd_free_irq_work);
+ fd_free_irq();
irqdma_allocated = 0;
}
set_dor(0, ~0, 8);
@@ -4600,8 +4568,6 @@ void cleanup_module(void)
/* eject disk, if any */
fd_eject(0);
- flush_scheduled_work(); /* fd_free_irq() might be pending */
-
wait_for_completion(&device_release);
}