scsi: sg: protect accesses to 'reserved' page array
The 'reserved' page array is used as a short-cut for mapping data, saving us to allocate pages per request. However, the 'reserved' array is only capable of holding one request, so this patch introduces a mutex for protect 'sg_fd' against concurrent accesses. 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>
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136e57bf43
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@ -142,6 +142,7 @@ typedef struct sg_fd { /* holds the state of a file descriptor */
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struct sg_device *parentdp; /* owning device */
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struct sg_device *parentdp; /* owning device */
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wait_queue_head_t read_wait; /* queue read until command done */
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wait_queue_head_t read_wait; /* queue read until command done */
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rwlock_t rq_list_lock; /* protect access to list in req_arr */
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rwlock_t rq_list_lock; /* protect access to list in req_arr */
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struct mutex f_mutex; /* protect against changes in this fd */
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int timeout; /* defaults to SG_DEFAULT_TIMEOUT */
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int timeout; /* defaults to SG_DEFAULT_TIMEOUT */
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int timeout_user; /* defaults to SG_DEFAULT_TIMEOUT_USER */
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int timeout_user; /* defaults to SG_DEFAULT_TIMEOUT_USER */
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Sg_scatter_hold reserve; /* buffer held for this file descriptor */
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Sg_scatter_hold reserve; /* buffer held for this file descriptor */
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@ -153,6 +154,7 @@ typedef struct sg_fd { /* holds the state of a file descriptor */
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unsigned char next_cmd_len; /* 0: automatic, >0: use on next write() */
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unsigned char next_cmd_len; /* 0: automatic, >0: use on next write() */
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char keep_orphan; /* 0 -> drop orphan (def), 1 -> keep for read() */
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char keep_orphan; /* 0 -> drop orphan (def), 1 -> keep for read() */
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char mmap_called; /* 0 -> mmap() never called on this fd */
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char mmap_called; /* 0 -> mmap() never called on this fd */
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char res_in_use; /* 1 -> 'reserve' array in use */
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struct kref f_ref;
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struct kref f_ref;
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struct execute_work ew;
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struct execute_work ew;
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} Sg_fd;
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} Sg_fd;
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@ -196,7 +198,6 @@ static void sg_remove_sfp(struct kref *);
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static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
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static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
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static Sg_request *sg_add_request(Sg_fd * sfp);
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static Sg_request *sg_add_request(Sg_fd * sfp);
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static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
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static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
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static int sg_res_in_use(Sg_fd * sfp);
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static Sg_device *sg_get_dev(int dev);
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static Sg_device *sg_get_dev(int dev);
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static void sg_device_destroy(struct kref *kref);
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static void sg_device_destroy(struct kref *kref);
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@ -612,6 +613,7 @@ sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
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}
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}
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buf += SZ_SG_HEADER;
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buf += SZ_SG_HEADER;
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__get_user(opcode, buf);
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__get_user(opcode, buf);
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mutex_lock(&sfp->f_mutex);
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if (sfp->next_cmd_len > 0) {
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if (sfp->next_cmd_len > 0) {
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cmd_size = sfp->next_cmd_len;
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cmd_size = sfp->next_cmd_len;
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sfp->next_cmd_len = 0; /* reset so only this write() effected */
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sfp->next_cmd_len = 0; /* reset so only this write() effected */
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@ -620,6 +622,7 @@ sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
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if ((opcode >= 0xc0) && old_hdr.twelve_byte)
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if ((opcode >= 0xc0) && old_hdr.twelve_byte)
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cmd_size = 12;
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cmd_size = 12;
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}
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}
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mutex_unlock(&sfp->f_mutex);
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SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
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SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
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"sg_write: scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
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"sg_write: scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
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/* Determine buffer size. */
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/* Determine buffer size. */
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@ -719,7 +722,7 @@ sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
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sg_remove_request(sfp, srp);
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sg_remove_request(sfp, srp);
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return -EINVAL; /* either MMAP_IO or DIRECT_IO (not both) */
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return -EINVAL; /* either MMAP_IO or DIRECT_IO (not both) */
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}
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}
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if (sg_res_in_use(sfp)) {
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if (sfp->res_in_use) {
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sg_remove_request(sfp, srp);
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sg_remove_request(sfp, srp);
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return -EBUSY; /* reserve buffer already being used */
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return -EBUSY; /* reserve buffer already being used */
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}
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}
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@ -953,12 +956,18 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
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return -EINVAL;
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return -EINVAL;
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val = min_t(int, val,
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val = min_t(int, val,
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max_sectors_bytes(sdp->device->request_queue));
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max_sectors_bytes(sdp->device->request_queue));
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mutex_lock(&sfp->f_mutex);
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if (val != sfp->reserve.bufflen) {
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if (val != sfp->reserve.bufflen) {
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if (sg_res_in_use(sfp) || sfp->mmap_called)
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if (sfp->mmap_called ||
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sfp->res_in_use) {
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mutex_unlock(&sfp->f_mutex);
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return -EBUSY;
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return -EBUSY;
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}
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sg_remove_scat(sfp, &sfp->reserve);
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sg_remove_scat(sfp, &sfp->reserve);
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sg_build_reserve(sfp, val);
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sg_build_reserve(sfp, val);
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}
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}
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mutex_unlock(&sfp->f_mutex);
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return 0;
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return 0;
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case SG_GET_RESERVED_SIZE:
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case SG_GET_RESERVED_SIZE:
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val = min_t(int, sfp->reserve.bufflen,
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val = min_t(int, sfp->reserve.bufflen,
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@ -1718,13 +1727,22 @@ sg_start_req(Sg_request *srp, unsigned char *cmd)
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md = &map_data;
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md = &map_data;
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if (md) {
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if (md) {
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if (!sg_res_in_use(sfp) && dxfer_len <= rsv_schp->bufflen)
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mutex_lock(&sfp->f_mutex);
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if (dxfer_len <= rsv_schp->bufflen &&
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!sfp->res_in_use) {
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sfp->res_in_use = 1;
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sg_link_reserve(sfp, srp, dxfer_len);
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sg_link_reserve(sfp, srp, dxfer_len);
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else {
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} else if ((hp->flags & SG_FLAG_MMAP_IO) && sfp->res_in_use) {
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mutex_unlock(&sfp->f_mutex);
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return -EBUSY;
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} else {
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res = sg_build_indirect(req_schp, sfp, dxfer_len);
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res = sg_build_indirect(req_schp, sfp, dxfer_len);
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if (res)
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if (res) {
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mutex_unlock(&sfp->f_mutex);
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return res;
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return res;
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}
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}
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}
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mutex_unlock(&sfp->f_mutex);
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md->pages = req_schp->pages;
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md->pages = req_schp->pages;
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md->page_order = req_schp->page_order;
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md->page_order = req_schp->page_order;
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@ -2125,6 +2143,7 @@ sg_add_sfp(Sg_device * sdp)
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rwlock_init(&sfp->rq_list_lock);
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rwlock_init(&sfp->rq_list_lock);
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kref_init(&sfp->f_ref);
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kref_init(&sfp->f_ref);
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mutex_init(&sfp->f_mutex);
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sfp->timeout = SG_DEFAULT_TIMEOUT;
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sfp->timeout = SG_DEFAULT_TIMEOUT;
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sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
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sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
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sfp->force_packid = SG_DEF_FORCE_PACK_ID;
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sfp->force_packid = SG_DEF_FORCE_PACK_ID;
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@ -2198,20 +2217,6 @@ sg_remove_sfp(struct kref *kref)
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schedule_work(&sfp->ew.work);
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schedule_work(&sfp->ew.work);
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}
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}
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static int
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sg_res_in_use(Sg_fd * sfp)
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{
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const Sg_request *srp;
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unsigned long iflags;
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read_lock_irqsave(&sfp->rq_list_lock, iflags);
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for (srp = sfp->headrp; srp; srp = srp->nextrp)
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if (srp->res_used)
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break;
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read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
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return srp ? 1 : 0;
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}
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#ifdef CONFIG_SCSI_PROC_FS
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#ifdef CONFIG_SCSI_PROC_FS
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static int
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static int
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sg_idr_max_id(int id, void *p, void *data)
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sg_idr_max_id(int id, void *p, void *data)
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