diff options
| author | Ian Munsie <imunsie@au1.ibm.com> | 2014-12-08 11:17:55 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2014-12-12 05:06:47 +0300 |
| commit | ee41d11d53c8fc4968f0816504651541d606cf40 (patch) | |
| tree | c3680cf3bdcfadcf5c23088fb8b3a75a4d48b6ef /drivers/misc/cxl/native.c | |
| parent | 7c5c92ed56d932b2c19c3f8aea86369509407d33 (diff) | |
| download | linux-ee41d11d53c8fc4968f0816504651541d606cf40.tar.xz | |
cxl: Change contexts_lock to a mutex to fix sleep while atomic bug
We had a known sleep while atomic bug if a CXL device was forcefully
unbound while it was in use. This could occur as a result of EEH, or
manually induced with something like this while the device was in use:
echo 0000:01:00.0 > /sys/bus/pci/drivers/cxl-pci/unbind
The issue was that in this code path we iterated over each context and
forcefully detached it with the contexts_lock spin lock held, however
the detach also needed to take the spu_mutex, and call schedule.
This patch changes the contexts_lock to a mutex so that we are not in
atomic context while doing the detach, thereby avoiding the sleep while
atomic.
Also delete the related TODO comment, which suggested an alternate
solution which turned out to not be workable.
Cc: stable@vger.kernel.org
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'drivers/misc/cxl/native.c')
| -rw-r--r-- | drivers/misc/cxl/native.c | 7 |
1 files changed, 0 insertions, 7 deletions
diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c index 9a5a442269a8..1001cf49af94 100644 --- a/drivers/misc/cxl/native.c +++ b/drivers/misc/cxl/native.c @@ -610,13 +610,6 @@ static inline int detach_process_native_dedicated(struct cxl_context *ctx) return 0; } -/* - * TODO: handle case when this is called inside a rcu_read_lock() which may - * happen when we unbind the driver (ie. cxl_context_detach_all()) . Terminate - * & remove use a mutex lock and schedule which will not good with lock held. - * May need to write do_process_element_cmd() that handles outstanding page - * faults synchronously. - */ static inline int detach_process_native_afu_directed(struct cxl_context *ctx) { if (!ctx->pe_inserted) |