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| author | Jan Kiszka <jan.kiszka@web.de> | 2010-02-08 11:12:15 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-02-17 01:01:22 +0100 |
| commit | 88c896ef87fd0dd4dbf36e8e86e019c74b1f6649 (patch) | |
| tree | 727de518c111fc1d3d3a3bf49ea292ea414e17c6 /drivers/isdn/capi/kcapi_proc.c | |
| parent | CAPI: Rework locking of controller data structures (diff) | |
| download | linux-88c896ef87fd0dd4dbf36e8e86e019c74b1f6649.tar.xz linux-88c896ef87fd0dd4dbf36e8e86e019c74b1f6649.zip | |
CAPI: Rework application locking
Drop the application rw-lock in favour of RCU. This synchronizes
capi20_release against capi_ctr_handle_message which may dereference an
application from (soft-)IRQ context. Any other access to the application
list is now protected by the capi_controller_lock as well. This also
allows to safely inspect applications for /proc dumping by holding
capi_controller_lock.
At this chance, drop some useless release_in_progress checks where we
obtained the application pointer from the list (which becomes NULL on
release_in_progress).
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/isdn/capi/kcapi_proc.c')
| -rw-r--r-- | drivers/isdn/capi/kcapi_proc.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/isdn/capi/kcapi_proc.c b/drivers/isdn/capi/kcapi_proc.c index 3e6e17a24389..ea2dff602e49 100644 --- a/drivers/isdn/capi/kcapi_proc.c +++ b/drivers/isdn/capi/kcapi_proc.c @@ -139,9 +139,11 @@ static const struct file_operations proc_contrstats_ops = { // applid nrecvctlpkt nrecvdatapkt nsentctlpkt nsentdatapkt // --------------------------------------------------------------------------- -static void * -applications_start(struct seq_file *seq, loff_t *pos) +static void *applications_start(struct seq_file *seq, loff_t *pos) + __acquires(capi_controller_lock) { + mutex_lock(&capi_controller_lock); + if (*pos < CAPI_MAXAPPL) return &capi_applications[*pos]; @@ -158,9 +160,10 @@ applications_next(struct seq_file *seq, void *v, loff_t *pos) return NULL; } -static void -applications_stop(struct seq_file *seq, void *v) +static void applications_stop(struct seq_file *seq, void *v) + __releases(capi_controller_lock) { + mutex_unlock(&capi_controller_lock); } static int |