[PATCH 4.9 48/77] scsi: sg: use standard lists for sg_requests

Greg Kroah-Hartman
2017-09-24T21:11:02Z

From: Hannes Reinecke <hare@suse.de>

commit 109bade9c625c89bb5ea753aaa1a0a97e6fbb548 upstream.

'Sg_request' is using a private list implementation; convert it to
standard lists.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/scsi/sg.c | 147 ++++++++++++++++++++++--------------------------------
1 file changed, 61 insertions(+), 86 deletions(-)

--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -122,7 +122,7 @@ struct sg_device; /* forward declaratio
struct sg_fd;

typedef struct sg_request { /* SG_MAX_QUEUE requests outstanding per file */
- struct sg_request *nextrp; /* NULL -> tail request (slist) */
+ struct list_head entry; /* list entry */
struct sg_fd *parentfp; /* NULL -> not in use */
Sg_scatter_hold data; /* hold buffer, perhaps scatter list */
sg_io_hdr_t header; /* scsi command+info, see <scsi/sg.h> */
@@ -146,7 +146,7 @@ typedef struct sg_fd { /* holds the sta
int timeout; /* defaults to SG_DEFAULT_TIMEOUT */
int timeout_user; /* defaults to SG_DEFAULT_TIMEOUT_USER */
Sg_scatter_hold reserve; /* buffer held for this file descriptor */
- Sg_request *headrp; /* head of request slist, NULL->empty */
+ struct list_head rq_list; /* head of request list */
struct fasync_struct *async_qp; /* used by asynchronous notification */
Sg_request req_arr[SG_MAX_QUEUE]; /* used as singly-linked list */
char low_dma; /* as in parent but possibly overridden to 1 */
@@ -940,7 +940,7 @@ sg_ioctl(struct file *filp, unsigned int
if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
return -EFAULT;
read_lock_irqsave(&sfp->rq_list_lock, iflags);
- for (srp = sfp->headrp; srp; srp = srp->nextrp) {
+ list_for_each_entry(srp, &sfp->rq_list, entry) {
if ((1 == srp->done) && (!srp->sg_io_owned)) {
read_unlock_irqrestore(&sfp->rq_list_lock,
iflags);
@@ -953,7 +953,8 @@ sg_ioctl(struct file *filp, unsigned int
return 0;
case SG_GET_NUM_WAITING:
read_lock_irqsave(&sfp->rq_list_lock, iflags);
- for (val = 0, srp = sfp->headrp; srp; srp = srp->nextrp) {
+ val = 0;
+ list_for_each_entry(srp, &sfp->rq_list, entry) {
if ((1 == srp->done) && (!srp->sg_io_owned))
++val;
}
@@ -1028,35 +1029,33 @@ sg_ioctl(struct file *filp, unsigned int
if (!rinfo)
return -ENOMEM;
read_lock_irqsave(&sfp->rq_list_lock, iflags);
- for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
- ++val, srp = srp ? srp->nextrp : srp) {
+ val = 0;
+ list_for_each_entry(srp, &sfp->rq_list, entry) {
+ if (val > SG_MAX_QUEUE)
+ break;
memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
- if (srp) {
- rinfo[val].req_state = srp->done + 1;
- rinfo[val].problem =
- srp->header.masked_status &
- srp->header.host_status &
- srp->header.driver_status;
- if (srp->done)
- rinfo[val].duration =
- srp->header.duration;
- else {
- ms = jiffies_to_msecs(jiffies);
- rinfo[val].duration =
- (ms > srp->header.duration) ?
- (ms - srp->header.duration) : 0;
- }
- rinfo[val].orphan = srp->orphan;
- rinfo[val].sg_io_owned =
- srp->sg_io_owned;
- rinfo[val].pack_id =
- srp->header.pack_id;
- rinfo[val].usr_ptr =
- srp->header.usr_ptr;
+ rinfo[val].req_state = srp->done + 1;
+ rinfo[val].problem =
+ srp->header.masked_status &
+ srp->header.host_status &
+ srp->header.driver_status;
+ if (srp->done)
+ rinfo[val].duration =
+ srp->header.duration;
+ else {
+ ms = jiffies_to_msecs(jiffies);
+ rinfo[val].duration =
+ (ms > srp->header.duration) ?
+ (ms - srp->header.duration) : 0;
}
+ rinfo[val].orphan = srp->orphan;
+ rinfo[val].sg_io_owned = srp->sg_io_owned;
+ rinfo[val].pack_id = srp->header.pack_id;
+ rinfo[val].usr_ptr = srp->header.usr_ptr;
+ val++;
}
read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
- result = __copy_to_user(p, rinfo,
+ result = __copy_to_user(p, rinfo,
SZ_SG_REQ_INFO * SG_MAX_QUEUE);
result = result ? -EFAULT : 0;
kfree(rinfo);
@@ -1162,7 +1161,7 @@ sg_poll(struct file *filp, poll_table *
return POLLERR;
poll_wait(filp, &sfp->read_wait, wait);
read_lock_irqsave(&sfp->rq_list_lock, iflags);
- for (srp = sfp->headrp; srp; srp = srp->nextrp) {
+ list_for_each_entry(srp, &sfp->rq_list, entry) {
/* if any read waiting, flag it */
if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
res = POLLIN | POLLRDNORM;
@@ -2060,7 +2059,7 @@ sg_get_rq_mark(Sg_fd * sfp, int pack_id)
unsigned long iflags;

write_lock_irqsave(&sfp->rq_list_lock, iflags);
- for (resp = sfp->headrp; resp; resp = resp->nextrp) {
+ list_for_each_entry(resp, &sfp->rq_list, entry) {
/* look for requests that are ready + not SG_IO owned */
if ((1 == resp->done) && (!resp->sg_io_owned) &&
((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
@@ -2078,70 +2077,45 @@ sg_add_request(Sg_fd * sfp)
{
int k;
unsigned long iflags;
- Sg_request *resp;
Sg_request *rp = sfp->req_arr;

write_lock_irqsave(&sfp->rq_list_lock, iflags);
- resp = sfp->headrp;
- if (!resp) {
- memset(rp, 0, sizeof (Sg_request));
- rp->parentfp = sfp;
- resp = rp;
- sfp->headrp = resp;
- } else {
- if (0 == sfp->cmd_q)
- resp = NULL; /* command queuing disallowed */
- else {
- for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
- if (!rp->parentfp)
- break;
- }
- if (k < SG_MAX_QUEUE) {
- memset(rp, 0, sizeof (Sg_request));
- rp->parentfp = sfp;
- while (resp->nextrp)
- resp = resp->nextrp;
- resp->nextrp = rp;
- resp = rp;
- } else
- resp = NULL;
+ if (!list_empty(&sfp->rq_list)) {
+ if (!sfp->cmd_q)
+ goto out_unlock;
+
+ for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
+ if (!rp->parentfp)
+ break;
}
+ if (k >= SG_MAX_QUEUE)
+ goto out_unlock;
}
- if (resp) {
- resp->nextrp = NULL;
- resp->header.duration = jiffies_to_msecs(jiffies);
- }
+ memset(rp, 0, sizeof (Sg_request));
+ rp->parentfp = sfp;
+ rp->header.duration = jiffies_to_msecs(jiffies);
+ list_add_tail(&rp->entry, &sfp->rq_list);
write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
- return resp;
+ return rp;
+out_unlock:
+ write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
+ return NULL;
}

/* Return of 1 for found; 0 for not found */
static int
sg_remove_request(Sg_fd * sfp, Sg_request * srp)
{
- Sg_request *prev_rp;
- Sg_request *rp;
unsigned long iflags;
int res = 0;

- if ((!sfp) || (!srp) || (!sfp->headrp))
+ if (!sfp || !srp || list_empty(&sfp->rq_list))
return res;
write_lock_irqsave(&sfp->rq_list_lock, iflags);
- prev_rp = sfp->headrp;
- if (srp == prev_rp) {
- sfp->headrp = prev_rp->nextrp;
- prev_rp->parentfp = NULL;
+ if (!list_empty(&srp->entry)) {
+ list_del(&srp->entry);
+ srp->parentfp = NULL;
res = 1;
- } else {
- while ((rp = prev_rp->nextrp)) {
- if (srp == rp) {
- prev_rp->nextrp = rp->nextrp;
- rp->parentfp = NULL;
- res = 1;
- break;
- }
- prev_rp = rp;
- }
}
write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
return res;
@@ -2160,7 +2134,7 @@ sg_add_sfp(Sg_device * sdp)

init_waitqueue_head(&sfp->read_wait);
rwlock_init(&sfp->rq_list_lock);
-
+ INIT_LIST_HEAD(&sfp->rq_list);
kref_init(&sfp->f_ref);
mutex_init(&sfp->f_mutex);
sfp->timeout = SG_DEFAULT_TIMEOUT;
@@ -2201,10 +2175,13 @@ sg_remove_sfp_usercontext(struct work_st
{
struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
struct sg_device *sdp = sfp->parentdp;
+ Sg_request *srp;

/* Cleanup any responses which were never read(). */
- while (sfp->headrp)
- sg_finish_rem_req(sfp->headrp);
+ while (!list_empty(&sfp->rq_list)) {
+ srp = list_first_entry(&sfp->rq_list, Sg_request, entry);
+ sg_finish_rem_req(srp);
+ }

if (sfp->reserve.bufflen > 0) {
SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
@@ -2607,7 +2584,7 @@ static int sg_proc_seq_show_devstrs(stru
/* must be called while holding sg_index_lock */
static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
{
- int k, m, new_interface, blen, usg;
+ int k, new_interface, blen, usg;
Sg_request *srp;
Sg_fd *fp;
const sg_io_hdr_t *hp;
@@ -2627,13 +2604,11 @@ static void sg_proc_debug_helper(struct
seq_printf(s, " cmd_q=%d f_packid=%d k_orphan=%d closed=0\n",
(int) fp->cmd_q, (int) fp->force_packid,
(int) fp->keep_orphan);
- for (m = 0, srp = fp->headrp;
- srp != NULL;
- ++m, srp = srp->nextrp) {
+ list_for_each_entry(srp, &fp->rq_list, entry) {
hp = &srp->header;
new_interface = (hp->interface_id == '\0') ? 0 : 1;
if (srp->res_used) {
- if (new_interface &&
+ if (new_interface &&
(SG_FLAG_MMAP_IO & hp->flags))
cp = " mmap>> ";
else
@@ -2664,7 +2639,7 @@ static void sg_proc_debug_helper(struct
seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
(int) srp->data.cmd_opcode);
}
- if (0 == m)
+ if (list_empty(&fp->rq_list))
seq_puts(s, " No requests active\n");
read_unlock(&fp->rq_list_lock);
}