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, Hannes Reinecke <hare@suse.com>
Subject: [PATCH v16 06/45] sg: make open count an atomic
Date: Fri, 19 Feb 2021 21:00:17 -0500 [thread overview]
Message-ID: <20210220020056.77483-7-dgilbert@interlog.com> (raw)
In-Reply-To: <20210220020056.77483-1-dgilbert@interlog.com>
Convert sg_device::open_cnt into an atomic. Also rename
sg_tablesize into the more descriptive max_sgat_elems.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
---
drivers/scsi/sg.c | 44 +++++++++++++++++++++++---------------------
1 file changed, 23 insertions(+), 21 deletions(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 087e2d7f5474..7f2a2d48d247 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;
@@ -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 */
@@ -328,7 +328,7 @@ sg_open(struct inode *inode, struct file *filp)
o_excl = !!(op_flags & O_EXCL);
if (o_excl && ((op_flags & O_ACCMODE) == O_RDONLY))
return -EPERM; /* Can't lock it with read only access */
- sdp = sg_get_dev(min_dev);
+ sdp = sg_get_dev(min_dev); /* increments sdp->d_ref */
if (IS_ERR(sdp))
return PTR_ERR(sdp);
@@ -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;
}
@@ -375,27 +375,29 @@ 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);
+ sfp = sg_add_sfp(sdp); /* increments sdp->d_ref */
if (IS_ERR(sfp)) {
retval = PTR_ERR(sfp);
goto out_undo;
}
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;
sg_put:
kref_put(&sdp->d_ref, sg_device_destroy);
+ /* if success, sdp->d_ref is incremented twice, decremented once */
return retval;
out_undo:
@@ -423,20 +425,20 @@ 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 exclude 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;
@@ -1110,7 +1112,7 @@ sg_ioctl_common(struct file *filp, struct sg_device *sdp, struct sg_fd *sfp,
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)
@@ -1589,7 +1591,7 @@ 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;
@@ -1985,7 +1987,7 @@ 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;
@@ -2000,7 +2002,7 @@ 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 */
@@ -2688,9 +2690,9 @@ 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);
--
2.25.1
next prev parent reply other threads:[~2021-02-20 2:03 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-20 2:00 [PATCH v16 00/45] sg: add v4 interface Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 01/45] sg: move functions around Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 02/45] sg: remove typedefs, type+formatting cleanup Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 03/45] sg: sg_log and is_enabled Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 04/45] sg: rework sg_poll(), minor changes Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 05/45] sg: bitops in sg_device Douglas Gilbert
2021-02-20 2:00 ` Douglas Gilbert [this message]
2021-02-20 2:00 ` [PATCH v16 07/45] sg: move header to uapi section Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 08/45] sg: speed sg_poll and sg_get_num_waiting Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 09/45] sg: sg_allow_if_err_recovery and renames Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 10/45] sg: improve naming Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 11/45] sg: change rwlock to spinlock Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 12/45] sg: ioctl handling Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 13/45] sg: split sg_read Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 14/45] sg: sg_common_write add structure for arguments Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 15/45] sg: rework sg_vma_fault Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 16/45] sg: rework sg_mmap Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 17/45] sg: replace sg_allow_access Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 18/45] sg: rework scatter gather handling Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 19/45] sg: introduce request state machine Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 20/45] sg: sg_find_srp_by_id Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 21/45] sg: sg_fill_request_element Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 22/45] sg: printk change %p to %pK Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 23/45] sg: xarray for fds in device Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 24/45] sg: xarray for reqs in fd Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 25/45] sg: replace rq array with xarray Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 26/45] sg: sense buffer rework Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 27/45] sg: add sg v4 interface support Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 28/45] sg: rework debug info Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 29/45] sg: add 8 byte SCSI LUN to sg_scsi_id Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 30/45] sg: expand sg_comm_wr_t Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 31/45] sg: add sg_iosubmit_v3 and sg_ioreceive_v3 ioctls Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 32/45] sg: add some __must_hold macros Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 33/45] sg: move procfs objects to avoid forward decls Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 34/45] sg: protect multiple receivers Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 35/45] sg: first debugfs support Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 36/45] sg: rework mmap support Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 37/45] sg: defang allow_dio Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 38/45] sg: warn v3 write system call users Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 39/45] sg: add mmap_sz tracking Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 40/45] sg: remove rcv_done request state Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 41/45] sg: track lowest inactive and await indexes Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 42/45] sg: remove unit attention check for device changed Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 43/45] sg: no_dxfer: move to/from kernel buffers Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 44/45] sg: add blk_poll support Douglas Gilbert
2021-02-20 2:00 ` [PATCH v16 45/45] sg: bump version to 4.0.12 Douglas Gilbert
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