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isdn: divert, hysdn: fix interruptible_sleep_on race

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These two drivers use identical code for their procfs status
file handling, which contains a small race against status
data becoming available while reading the file.

This uses wait_event_interruptible instead to fix this
particular race and eventually get rid of all sleep_on
instances. There seems to be another race involving
multiple concurrent readers of the same procfs file, which
I don't try to fix here.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Arnd Bergmann 2014-02-26 12:01:54 +01:00 committed by David S. Miller
parent c728cc88ce
commit c11da83bda
2 changed files with 8 additions and 6 deletions
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7
drivers/isdn/divert/divert_procfs.c
View File

@ -86,12 +86,13 @@ isdn_divert_read(struct file *file, char __user *buf, size_t count, loff_t *off)
struct divert_info *inf; struct divert_info *inf;
int len; int len;
if (!*((struct divert_info **) file->private_data)) { if (!(inf = *((struct divert_info **) file->private_data))) {
if (file->f_flags & O_NONBLOCK) if (file->f_flags & O_NONBLOCK)
return -EAGAIN; return -EAGAIN;
interruptible_sleep_on(&(rd_queue)); wait_event_interruptible(rd_queue, (inf =
*((struct divert_info **) file->private_data)));
} }
if (!(inf = *((struct divert_info **) file->private_data))) if (!inf)
return (0); return (0);
inf->usage_cnt--; /* new usage count */ inf->usage_cnt--; /* new usage count */

7
drivers/isdn/hysdn/hysdn_proclog.c
View File

@ -175,14 +175,15 @@ hysdn_log_read(struct file *file, char __user *buf, size_t count, loff_t *off)
int len; int len;
hysdn_card *card = PDE_DATA(file_inode(file)); hysdn_card *card = PDE_DATA(file_inode(file));
if (!*((struct log_data **) file->private_data)) { if (!(inf = *((struct log_data **) file->private_data))) {
struct procdata *pd = card->proclog; struct procdata *pd = card->proclog;
if (file->f_flags & O_NONBLOCK) if (file->f_flags & O_NONBLOCK)
return (-EAGAIN); return (-EAGAIN);
interruptible_sleep_on(&(pd->rd_queue)); wait_event_interruptible(pd->rd_queue, (inf =
*((struct log_data **) file->private_data)));
} }
if (!(inf = *((struct log_data **) file->private_data))) if (!inf)
return (0); return (0);
inf->usage_cnt--; /* new usage count */ inf->usage_cnt--; /* new usage count */