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cam_sim: harmonize code related to acquiring a mtx

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cam_sim_free(), cam_sim_release(), and cam_sim_hold() all assign
a mtx variable during declaration and then if NULL or the mtx is
held may re-asign the variable and/or acquire/release a lock.

Harmonize the code, avoiding double assignments and make it look
the same for all three function (with cam_sim_free() not needing
an extra case).

No functional changes intended.

Reviewed by:	imp; no-objections by: mav
MFC after:	3 days
Differential Revision:	https://reviews.freebsd.org/D26286
This commit is contained in:
Bjoern A. Zeeb 2020-09-04 18:18:05 +00:00
parent 1bd641af2b
commit 7a7ca53f69
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=365333
1 changed files with 20 additions and 21 deletions
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41
sys/cam/cam_sim.c
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@ -124,14 +124,15 @@ cam_sim_alloc_dev(sim_action_func sim_action, sim_poll_func sim_poll,
void
cam_sim_free(struct cam_sim *sim, int free_devq)
{
struct mtx *mtx = sim->mtx;
struct mtx *mtx;
int error;
if (mtx) {
mtx_assert(mtx, MA_OWNED);
} else {
if (sim->mtx == NULL) {
mtx = &cam_sim_free_mtx;
mtx_lock(mtx);
} else {
mtx = sim->mtx;
mtx_assert(mtx, MA_OWNED);
}
sim->refcount--;
if (sim->refcount > 0) {
@ -139,7 +140,7 @@ cam_sim_free(struct cam_sim *sim, int free_devq)
KASSERT(error == 0, ("invalid error value for msleep(9)"));
}
KASSERT(sim->refcount == 0, ("sim->refcount == 0"));
if (sim->mtx == NULL)
if (mtx == &cam_sim_free_mtx) /* sim->mtx == NULL */
mtx_unlock(mtx);
if (free_devq)
@ -150,17 +151,16 @@ cam_sim_free(struct cam_sim *sim, int free_devq)
void
cam_sim_release(struct cam_sim *sim)
{
struct mtx *mtx = sim->mtx;
struct mtx *mtx;
if (mtx) {
if (!mtx_owned(mtx))
mtx_lock(mtx);
else
mtx = NULL;
} else {
if (sim->mtx == NULL)
mtx = &cam_sim_free_mtx;
else if (!mtx_owned(sim->mtx))
mtx = sim->mtx;
else
mtx = NULL; /* We hold the lock. */
if (mtx)
mtx_lock(mtx);
}
KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
sim->refcount--;
if (sim->refcount == 0)
@ -172,17 +172,16 @@ cam_sim_release(struct cam_sim *sim)
void
cam_sim_hold(struct cam_sim *sim)
{
struct mtx *mtx = sim->mtx;
struct mtx *mtx;
if (mtx) {
if (!mtx_owned(mtx))
mtx_lock(mtx);
else
mtx = NULL;
} else {
if (sim->mtx == NULL)
mtx = &cam_sim_free_mtx;
else if (!mtx_owned(sim->mtx))
mtx = sim->mtx;
else
mtx = NULL; /* We hold the lock. */
if (mtx)
mtx_lock(mtx);
}
KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
sim->refcount++;
if (mtx)