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[PATCH 1/5] staging:lustre: kg_sem semaphore handling is incorrectly

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During the removal of the cfs wrappers the kg_sem semaphore
was handled incorrectly. We need to take a write lock when
writing data to the kkuc_groups. The libcfs_kkuc_group_foreach
needs to only take a read lock. This makes use match the
OpenSFS development branch.

Signed-off-by: James Simmons <jsimmons@infradead.org>
---
 .../lustre/lustre/libcfs/kernel_user_comm.c        |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/lustre/lustre/libcfs/kernel_user_comm.c b/drivers/staging/lustre/lustre/libcfs/kernel_user_comm.c
index d9b7c6b..48df275 100644
--- a/drivers/staging/lustre/lustre/libcfs/kernel_user_comm.c
+++ b/drivers/staging/lustre/lustre/libcfs/kernel_user_comm.c
@@ -184,7 +184,7 @@ int libcfs_kkuc_group_put(int group, void *payload)
 	int		 rc = 0;
 	int one_success = 0;
 
-	down_read(&kg_sem);
+	down_write(&kg_sem);
 	list_for_each_entry(reg, &kkuc_groups[group], kr_chain) {
 		if (reg->kr_fp != NULL) {
 			rc = libcfs_kkuc_msg_put(reg->kr_fp, payload);
@@ -196,7 +196,7 @@ int libcfs_kkuc_group_put(int group, void *payload)
 			}
 		}
 	}
-	up_read(&kg_sem);
+	up_write(&kg_sem);
 
 	/* don't return an error if the message has been delivered
 	 * at least to one agent */
@@ -228,12 +228,12 @@ int libcfs_kkuc_group_foreach(int group, libcfs_kkuc_cb_t cb_func,
 	if (kkuc_groups[group].next == NULL)
 		return 0;
 
-	down_write(&kg_sem);
+	down_read(&kg_sem);
 	list_for_each_entry(reg, &kkuc_groups[group], kr_chain) {
 		if (reg->kr_fp != NULL)
 			rc = cb_func(reg->kr_data, cb_arg);
 	}
-	up_write(&kg_sem);
+	up_read(&kg_sem);
 
 	return rc;
 }
-- 
1.7.1

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[PATCH 0/5] staging:lustre: split kernel comm between user and kernel James Simmons <jsimmons@infradead.org> - 2015-10-23 22:00 +0200
  [PATCH] staging:lustre: Prevent duplicate CT registrations James Simmons <jsimmons@infradead.org> - 2015-10-23 22:10 +0200
    Re: [PATCH] staging:lustre: Prevent duplicate CT registrations Dan Carpenter <dan.carpenter@oracle.com> - 2015-10-26 10:00 +0100
  [PATCH 1/5] staging:lustre: kg_sem semaphore handling is incorrectly James Simmons <jsimmons@infradead.org> - 2015-10-23 22:10 +0200
  [PATCH 4/5] staging:lustre: split kernel comm between user and kernel James Simmons <jsimmons@infradead.org> - 2015-10-23 22:10 +0200
  [PATCH] staging:lustre: move kernel_user_comm.c from libcfs to lustre James Simmons <jsimmons@infradead.org> - 2015-10-23 22:10 +0200
  [PATCH 5/5] staging:lustre: Update license and copyright for kernel comm James Simmons <jsimmons@infradead.org> - 2015-10-23 22:10 +0200
  Re: [PATCH 0/5] staging:lustre: split kernel comm between user and  kernel Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-10-25 09:40 +0100

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