From: Douglas Gilbert <dgilbert@interlog.com>
To: linux-scsi@vger.kernel.org
Cc: martin.petersen@oracle.com, jejb@linux.vnet.ibm.com,
hare@suse.de, bvanassche@acm.org
Subject: [PATCH v3 06/20] sg: make open count an atomic
Date: Wed, 7 Aug 2019 13:42:38 +0200 [thread overview]
Message-ID: <20190807114252.2565-7-dgilbert@interlog.com> (raw)
In-Reply-To: <20190807114252.2565-1-dgilbert@interlog.com>
Convert sg_device::open_cnt into an atomic. Also rename
sg_tablesize into the more descriptive max_sgat_elems.
Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
---
drivers/scsi/sg.c | 39 ++++++++++++++++++++-------------------
1 file changed, 20 insertions(+), 19 deletions(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 97ce84f0c51b..9e9470944fe3 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -162,9 +162,9 @@ struct sg_device { /* holds the state of each scsi generic device */
struct mutex open_rel_lock; /* held when in open() or release() */
struct list_head sfds;
rwlock_t sfd_lock; /* protect access to sfd list */
- int sg_tablesize; /* adapter's max scatter-gather table size */
+ int max_sgat_elems; /* adapter's max sgat number of elements */
u32 index; /* device index number */
- int open_cnt; /* count of opens (perhaps < num(sfds) ) */
+ atomic_t open_cnt; /* count of opens (perhaps < num(sfds) ) */
unsigned long fdev_bm[1]; /* see SG_FDEV_* defines above */
struct gendisk *disk;
struct cdev * cdev; /* char_dev [sysfs: /sys/cdev/major/sg<n>] */
@@ -276,11 +276,11 @@ sg_wait_open_event(struct sg_device *sdp, bool o_excl)
int retval = 0;
if (o_excl) {
- while (sdp->open_cnt > 0) {
+ while (atomic_read(&sdp->open_cnt) > 0) {
mutex_unlock(&sdp->open_rel_lock);
retval = wait_event_interruptible(sdp->open_wait,
(SG_IS_DETACHING(sdp) ||
- !sdp->open_cnt));
+ atomic_read(&sdp->open_cnt) == 0));
mutex_lock(&sdp->open_rel_lock);
if (retval) /* -ERESTARTSYS */
@@ -355,7 +355,7 @@ sg_open(struct inode *inode, struct file *filp)
mutex_lock(&sdp->open_rel_lock);
if (op_flags & O_NONBLOCK) {
if (o_excl) {
- if (sdp->open_cnt > 0) {
+ if (atomic_read(&sdp->open_cnt) > 0) {
retval = -EBUSY;
goto error_mutex_locked;
}
@@ -375,10 +375,10 @@ sg_open(struct inode *inode, struct file *filp)
if (o_excl)
set_bit(SG_FDEV_EXCLUDE, sdp->fdev_bm);
- if (sdp->open_cnt < 1) { /* no existing opens */
+ if (atomic_read(&sdp->open_cnt) < 1) { /* no existing opens */
clear_bit(SG_FDEV_LOG_SENSE, sdp->fdev_bm);
q = sdp->device->request_queue;
- sdp->sg_tablesize = queue_max_segments(q);
+ sdp->max_sgat_elems = queue_max_segments(q);
}
sfp = sg_add_sfp(sdp);
if (IS_ERR(sfp)) {
@@ -387,10 +387,11 @@ sg_open(struct inode *inode, struct file *filp)
}
filp->private_data = sfp;
- sdp->open_cnt++;
+ atomic_inc(&sdp->open_cnt);
mutex_unlock(&sdp->open_rel_lock);
SG_LOG(3, sfp, "%s: minor=%d, op_flags=0x%x; %s count prior=%d%s\n",
- __func__, min_dev, op_flags, "device open", sdp->open_cnt,
+ __func__, min_dev, op_flags, "device open",
+ atomic_read(&sdp->open_cnt),
((op_flags & O_NONBLOCK) ? " O_NONBLOCK" : ""));
retval = 0;
@@ -423,20 +424,20 @@ sg_release(struct inode *inode, struct file *filp)
sfp = filp->private_data;
sdp = sfp->parentdp;
SG_LOG(3, sfp, "%s: device open count prior=%d\n", __func__,
- sdp->open_cnt);
+ atomic_read(&sdp->open_cnt));
if (!sdp)
return -ENXIO;
mutex_lock(&sdp->open_rel_lock);
scsi_autopm_put_device(sdp->device);
kref_put(&sfp->f_ref, sg_remove_sfp);
- sdp->open_cnt--;
+ atomic_dec(&sdp->open_cnt);
/* possibly many open()s waiting on exlude clearing, start many;
* only open(O_EXCL)s wait on 0==open_cnt so only start one */
if (test_and_clear_bit(SG_FDEV_EXCLUDE, sdp->fdev_bm))
wake_up_interruptible_all(&sdp->open_wait);
- else if (sdp->open_cnt == 0)
+ else if (atomic_read(&sdp->open_cnt) == 0)
wake_up_interruptible(&sdp->open_wait);
mutex_unlock(&sdp->open_rel_lock);
return 0;
@@ -1104,7 +1105,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
return put_user(val, ip);
case SG_GET_SG_TABLESIZE:
- return put_user(sdp->sg_tablesize, ip);
+ return put_user(sdp->max_sgat_elems, ip);
case SG_SET_RESERVED_SIZE:
result = get_user(val, ip);
if (result)
@@ -1563,7 +1564,7 @@ sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
init_waitqueue_head(&sdp->open_wait);
clear_bit(SG_FDEV_DETACHING, sdp->fdev_bm);
rwlock_init(&sdp->sfd_lock);
- sdp->sg_tablesize = queue_max_segments(q);
+ sdp->max_sgat_elems = queue_max_segments(q);
sdp->index = k;
kref_init(&sdp->d_ref);
error = 0;
@@ -1958,7 +1959,7 @@ sg_build_indirect(struct sg_scatter_hold *schp, struct sg_fd *sfp,
int buff_size)
{
int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems;
- int sg_tablesize = sfp->parentdp->sg_tablesize;
+ int max_sgat_elems = sfp->parentdp->max_sgat_elems;
int blk_size = buff_size, order;
gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN | __GFP_ZERO;
struct sg_device *sdp = sfp->parentdp;
@@ -1973,7 +1974,7 @@ sg_build_indirect(struct sg_scatter_hold *schp, struct sg_fd *sfp,
blk_size);
/* N.B. ret_sz carried into this block ... */
- mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
+ mx_sc_elems = sg_build_sgat(schp, sfp, max_sgat_elems);
if (mx_sc_elems < 0)
return mx_sc_elems; /* most likely -ENOMEM */
@@ -2662,9 +2663,9 @@ sg_proc_seq_show_debug(struct seq_file *s, void *v)
scsidp->lun,
scsidp->host->hostt->emulated);
}
- seq_printf(s, " sg_tablesize=%d excl=%d open_cnt=%d\n",
- sdp->sg_tablesize, SG_HAVE_EXCLUDE(sdp),
- sdp->open_cnt);
+ seq_printf(s, " max_sgat_elems=%d excl=%d open_cnt=%d\n",
+ sdp->max_sgat_elems, SG_HAVE_EXCLUDE(sdp),
+ atomic_read(&sdp->open_cnt));
sg_proc_debug_helper(s, sdp);
}
read_unlock(&sdp->sfd_lock);
--
2.22.0
next prev parent reply other threads:[~2019-08-07 11:43 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-07 11:42 [PATCH v3 00/20] sg: add v4 interface Douglas Gilbert
2019-08-07 11:42 ` [PATCH v3 01/20] sg: move functions around Douglas Gilbert
2019-08-12 14:22 ` Christoph Hellwig
2019-08-07 11:42 ` [PATCH v3 02/20] sg: remove typedefs, type+formatting cleanup Douglas Gilbert
2019-08-12 14:22 ` Christoph Hellwig
2019-08-07 11:42 ` [PATCH v3 03/20] sg: sg_log and is_enabled Douglas Gilbert
2019-08-12 14:23 ` Christoph Hellwig
2019-08-13 22:57 ` Douglas Gilbert
2019-08-07 11:42 ` [PATCH v3 04/20] sg: rework sg_poll(), minor changes Douglas Gilbert
2019-08-12 14:23 ` Christoph Hellwig
2019-08-13 0:35 ` Douglas Gilbert
2019-08-07 11:42 ` [PATCH v3 05/20] sg: bitops in sg_device Douglas Gilbert
2019-08-12 14:23 ` Christoph Hellwig
2019-08-14 1:35 ` Douglas Gilbert
2019-08-07 11:42 ` Douglas Gilbert [this message]
2019-08-12 14:23 ` [PATCH v3 06/20] sg: make open count an atomic Christoph Hellwig
2019-08-07 11:42 ` [PATCH v3 07/20] sg: move header to uapi section Douglas Gilbert
2019-08-12 14:24 ` Christoph Hellwig
2019-08-12 14:32 ` Greg KH
2019-08-12 14:35 ` James Bottomley
2019-08-13 0:21 ` Douglas Gilbert
2019-08-07 11:42 ` [PATCH v3 08/20] sg: speed sg_poll and sg_get_num_waiting Douglas Gilbert
2019-08-12 14:31 ` Christoph Hellwig
2019-08-12 16:31 ` Douglas Gilbert
2019-08-07 11:42 ` [PATCH v3 09/20] sg: sg_allow_if_err_recovery and renames Douglas Gilbert
2019-08-12 14:31 ` Christoph Hellwig
2019-08-14 1:26 ` Douglas Gilbert
2019-08-07 11:42 ` [PATCH v3 10/20] sg: remove most access_ok functions Douglas Gilbert
2019-08-12 14:32 ` Christoph Hellwig
2019-08-07 11:42 ` [PATCH v3 11/20] sg: replace rq array with lists Douglas Gilbert
2019-08-12 14:35 ` Christoph Hellwig
2019-08-13 23:46 ` Douglas Gilbert
2019-08-07 11:42 ` [PATCH v3 12/20] sg: sense buffer rework Douglas Gilbert
2019-08-12 14:37 ` Christoph Hellwig
2019-08-12 16:26 ` Douglas Gilbert
2019-08-07 11:42 ` [PATCH v3 13/20] sg: add sg v4 interface support Douglas Gilbert
2019-08-09 23:12 ` James Bottomley
2019-08-11 19:21 ` Douglas Gilbert
2019-08-07 11:42 ` [PATCH v3 14/20] sg: rework debug info Douglas Gilbert
2019-08-07 11:42 ` [PATCH v3 15/20] sg: add 8 byte SCSI LUN to sg_scsi_id Douglas Gilbert
2019-08-07 11:42 ` [PATCH v3 16/20] sg: expand sg_comm_wr_t Douglas Gilbert
2019-08-07 11:42 ` [PATCH v3 17/20] sg: add sg_iosubmit_v3 and sg_ioreceive_v3 ioctls Douglas Gilbert
2019-08-09 23:15 ` James Bottomley
2019-08-12 15:37 ` Douglas Gilbert
2019-08-12 16:14 ` Tony Battersby
2019-08-12 18:46 ` James Bottomley
2019-08-12 19:37 ` Tony Battersby
2019-08-07 11:42 ` [PATCH v3 18/20] sg: add some __must_hold macros Douglas Gilbert
2019-08-07 11:42 ` [PATCH v3 19/20] sg: first debugfs support Douglas Gilbert
2019-08-07 11:42 ` [PATCH v3 20/20] sg: bump version to 4.0.03 Douglas Gilbert
2019-08-08 19:10 ` [PATCH v3 00/20] sg: add v4 interface James Bottomley
2019-08-08 21:08 ` Douglas Gilbert
2019-08-08 21:37 ` Tony Battersby
2019-08-08 22:25 ` Bart Van Assche
2019-08-09 13:28 ` Tony Battersby
2019-08-08 23:00 ` James Bottomley
2019-08-14 4:19 ` Douglas Gilbert
2019-08-15 17:30 ` Bart Van Assche
2019-08-16 15:59 ` Douglas Gilbert
2019-08-16 17:19 ` Greg KH
2019-08-16 18:10 ` Bart Van Assche
2019-08-16 18:44 ` Douglas Gilbert
2019-08-12 15:23 ` Christoph Hellwig
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