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| author | Vaibhav Jain <vaibhav@linux.vnet.ibm.com> | 2015-11-24 16:26:18 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2016-01-05 16:28:25 +1100 |
| commit | 7b8ad495d59280b634a7b546f4cdf58cf4d65f61 (patch) | |
| tree | 5681698cd7d7bebc66d1e32eececf99e6c0ec8c4 /drivers/misc/cxl/cxl.h | |
| parent | dc3799bb9ab2666fa19081121f05a4e573ecae12 (diff) | |
| download | linux-7b8ad495d59280b634a7b546f4cdf58cf4d65f61.tar.bz2 | |
cxl: Fix DSI misses when the context owning task exits
Presently when a user-space process issues CXL_IOCTL_START_WORK ioctl we
store the pid of the current task_struct and use it to get pointer to
the mm_struct of the process, while processing page or segment faults
from the capi card. However this causes issues when the thread that had
originally issued the start-work ioctl exits in which case the stored
pid is no more valid and the cxl driver is unable to handle faults as
the mm_struct corresponding to process is no more accessible.
This patch fixes this issue by using the mm_struct of the next alive
task in the thread group. This is done by iterating over all the tasks
in the thread group starting from thread group leader and calling
get_task_mm on each one of them. When a valid mm_struct is obtained the
pid of the associated task is stored in the context replacing the
exiting one for handling future faults.
The patch introduces a new function named get_mem_context that checks if
the current task pointed to by ctx->pid is dead? If yes it performs the
steps described above. Also a new variable cxl_context.glpid is
introduced which stores the pid of the thread group leader associated
with the context owning task.
Reported-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Reported-by: Frank Haverkamp <HAVERKAM@de.ibm.com>
Suggested-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Reviewed-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Reviewed-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'drivers/misc/cxl/cxl.h')
| -rw-r--r-- | drivers/misc/cxl/cxl.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h index 25ae57fa79b0..a521bc72cec2 100644 --- a/drivers/misc/cxl/cxl.h +++ b/drivers/misc/cxl/cxl.h @@ -445,6 +445,9 @@ struct cxl_context { unsigned int sst_size, sst_lru; wait_queue_head_t wq; + /* pid of the group leader associated with the pid */ + struct pid *glpid; + /* use mm context associated with this pid for ds faults */ struct pid *pid; spinlock_t lock; /* Protects pending_irq_mask, pending_fault and fault_addr */ /* Only used in PR mode */ |