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module/idxd: add lock around idxd device selection

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Without it multiple threads can race and end up sharing a device
when the intention is sharing only after full round robin.

Signed-off-by: paul luse <paul.e.luse@intel.com>
Change-Id: I29b854ff837d56078bc033802d3df244728a29aa
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/8187
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Mellanox Build Bot
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
This commit is contained in:
paul luse 2021-06-04 20:12:38 -04:00 committed by Jim Harris
parent 3bbfbb5b0f
commit bb8102b1ff
1 changed files with 7 additions and 2 deletions
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9
module/accel/idxd/accel_engine_idxd.c
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@ -65,6 +65,7 @@ struct idxd_device {
static TAILQ_HEAD(, idxd_device) g_idxd_devices = TAILQ_HEAD_INITIALIZER(g_idxd_devices); static TAILQ_HEAD(, idxd_device) g_idxd_devices = TAILQ_HEAD_INITIALIZER(g_idxd_devices);
static struct idxd_device *g_next_dev = NULL; static struct idxd_device *g_next_dev = NULL;
static uint32_t g_num_devices = 0; static uint32_t g_num_devices = 0;
static pthread_mutex_t g_dev_lock = PTHREAD_MUTEX_INITIALIZER;
struct idxd_io_channel { struct idxd_io_channel {
struct spdk_idxd_io_channel *chan; struct spdk_idxd_io_channel *chan;
@ -82,6 +83,7 @@ static struct idxd_device *
idxd_select_device(struct idxd_io_channel *chan) idxd_select_device(struct idxd_io_channel *chan)
{ {
uint32_t count = 0; uint32_t count = 0;
struct idxd_device *dev;
/* /*
* We allow channels to share underlying devices, * We allow channels to share underlying devices,
@ -90,20 +92,23 @@ idxd_select_device(struct idxd_io_channel *chan)
*/ */
do { do {
/* select next device */ /* select next device */
pthread_mutex_lock(&g_dev_lock);
g_next_dev = TAILQ_NEXT(g_next_dev, tailq); g_next_dev = TAILQ_NEXT(g_next_dev, tailq);
if (g_next_dev == NULL) { if (g_next_dev == NULL) {
g_next_dev = TAILQ_FIRST(&g_idxd_devices); g_next_dev = TAILQ_FIRST(&g_idxd_devices);
} }
dev = g_next_dev;
pthread_mutex_unlock(&g_dev_lock);
/* /*
* Now see if a channel is available on this one. We only * Now see if a channel is available on this one. We only
* allow a specific number of channels to share a device * allow a specific number of channels to share a device
* to limit outstanding IO for flow control purposes. * to limit outstanding IO for flow control purposes.
*/ */
chan->chan = spdk_idxd_get_channel(g_next_dev->idxd); chan->chan = spdk_idxd_get_channel(dev->idxd);
if (chan->chan != NULL) { if (chan->chan != NULL) {
chan->max_outstanding = spdk_idxd_chan_get_max_operations(chan->chan); chan->max_outstanding = spdk_idxd_chan_get_max_operations(chan->chan);
return g_next_dev; return dev;
} }
} while (count++ < g_num_devices); } while (count++ < g_num_devices);