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Subject[PATCH] nfp: Improve unlocking of a mutex in area_cache_get()
Date
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sat, 28 Oct 2017 17:12:10 +0200

Add a jump target so that a call of the function "mutex_unlock" is stored
only once at the end of this function implementation.
Replace four calls by goto statements.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
.../ethernet/netronome/nfp/nfpcore/nfp_cppcore.c | 28 ++++++++++------------
1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
index 04dd5758ecf5..e864793b7ca0 100644
--- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
+++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
@@ -822,10 +822,8 @@ area_cache_get(struct nfp_cpp *cpp, u32 id,

mutex_lock(&cpp->area_cache_mutex);

- if (list_empty(&cpp->area_cache_list)) {
- mutex_unlock(&cpp->area_cache_mutex);
- return NULL;
- }
+ if (list_empty(&cpp->area_cache_list))
+ goto unlock;

addr += *offset;

@@ -843,10 +841,8 @@ area_cache_get(struct nfp_cpp *cpp, u32 id,

/* Can we fit in the cache entry? */
if (round_down(addr + length - 1, cache->size) !=
- round_down(addr, cache->size)) {
- mutex_unlock(&cpp->area_cache_mutex);
- return NULL;
- }
+ round_down(addr, cache->size))
+ goto unlock;

/* If id != 0, we will need to release it */
if (cache->id) {
@@ -863,23 +859,23 @@ area_cache_get(struct nfp_cpp *cpp, u32 id,
if (cpp->op->area_init) {
err = cpp->op->area_init(cache->area,
id, cache->addr, cache->size);
- if (err < 0) {
- mutex_unlock(&cpp->area_cache_mutex);
- return NULL;
- }
+ if (err < 0)
+ goto unlock;
}

/* Attempt to acquire */
err = nfp_cpp_area_acquire(cache->area);
- if (err < 0) {
- mutex_unlock(&cpp->area_cache_mutex);
- return NULL;
- }
+ if (err < 0)
+ goto unlock;

exit:
/* Adjust offset */
*offset = addr - cache->addr;
return cache;
+
+unlock:
+ mutex_unlock(&cpp->area_cache_mutex);
+ return NULL;
}

static void
--
2.14.3
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