All of lore.kernel.org
 help / color / mirror / Atom feed
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
Subject: [PATCH v5 14/23] sg: split sg_read
Date: Tue,  8 Oct 2019 09:50:13 +0200	[thread overview]
Message-ID: <20191008075022.30055-15-dgilbert@interlog.com> (raw)
In-Reply-To: <20191008075022.30055-1-dgilbert@interlog.com>

As sg_read() is getting quite long, split out the v1 and v2
processing into sg_rd_v1v2(). Rename sg_new_read() to
sg_v3_receive() as the v3 interface is now older than the v4
interface which is being added in a later patch.

Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
---
 drivers/scsi/sg.c | 273 +++++++++++++++++++++++-----------------------
 1 file changed, 135 insertions(+), 138 deletions(-)

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 90753f7759c7..cbd75e34ca4b 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -760,17 +760,12 @@ sg_get_rq_mark(struct sg_fd *sfp, int pack_id)
 }
 
 static ssize_t
-sg_new_read(struct sg_fd *sfp, char __user *buf, size_t count,
-	    struct sg_request *srp)
+sg_v3_receive(struct sg_fd *sfp, char __user *buf, struct sg_request *srp)
 {
 	struct sg_io_hdr *hp = &srp->header;
 	int err = 0, err2;
 	int len;
 
-	if (count < SZ_SG_IO_HDR) {
-		err = -EINVAL;
-		goto err_out;
-	}
 	hp->sb_len_wr = 0;
 	if ((hp->mx_sb_len > 0) && hp->sbp) {
 		if ((CHECK_CONDITION & hp->masked_status) ||
@@ -791,14 +786,15 @@ sg_new_read(struct sg_fd *sfp, char __user *buf, size_t count,
 	}
 	if (hp->masked_status || hp->host_status || hp->driver_status)
 		hp->info |= SG_INFO_CHECK;
-	if (copy_to_user(buf, hp, SZ_SG_IO_HDR)) {
+	if (copy_to_user(buf, hp, SZ_SG_IO_HDR))
 		err = -EFAULT;
-		goto err_out;
-	}
+
 err_out:
 	err2 = sg_finish_scsi_blk_rq(srp);
+	if (err2)
+		err = err ? err : err2;
 	sg_remove_request(sfp, srp);
-	return err ? : err2 ? : count;
+	return err ? err : 0;
 }
 
 static int
@@ -813,164 +809,165 @@ srp_done(struct sg_fd *sfp, struct sg_request *srp)
 	return ret;
 }
 
-static ssize_t
-sg_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
+static int
+sg_rd_v1v2(void __user *buf, int count, struct sg_fd *sfp,
+	   struct sg_request *srp)
 {
-	struct sg_device *sdp;
-	struct sg_fd *sfp;
-	struct sg_request *srp;
-	int req_pack_id = -1;
-	int ret = 0;
-	struct sg_io_hdr *hp;
-	struct sg_header *old_hdr = NULL;
-
-	/*
-	 * This could cause a response to be stranded. Close the associated
-	 * file descriptor to free up any resources being held.
-	 */
-	ret = sg_check_file_access(filp, __func__);
-	if (ret)
-		return ret;
-
-	sfp = filp->private_data;
-	sdp = sfp->parentdp;
-	SG_LOG(3, sfp, "%s: read() count=%d\n", __func__, (int)count);
-	ret = sg_allow_if_err_recovery(sdp, false);
-	if (ret)
-		return ret;
-
-	if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
-		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
-		if (!old_hdr)
-			return -ENOMEM;
-		if (copy_from_user(old_hdr, buf, SZ_SG_HEADER)) {
-			ret = -EFAULT;
-			goto free_old_hdr;
-		}
-		if (old_hdr->reply_len < 0) {
-			if (count >= SZ_SG_IO_HDR) {
-				struct sg_io_hdr *new_hdr;
-
-				new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
-				if (!new_hdr) {
-					ret = -ENOMEM;
-					goto free_old_hdr;
-				}
-				ret = copy_from_user(new_hdr, buf,
-						     SZ_SG_IO_HDR);
-				req_pack_id = new_hdr->pack_id;
-				kfree(new_hdr);
-				if (ret) {
-					ret = -EFAULT;
-					goto free_old_hdr;
-				}
-			}
-		} else
-			req_pack_id = old_hdr->pack_id;
-	}
-	srp = sg_get_rq_mark(sfp, req_pack_id);
-	if (!srp) {		/* now wait on packet to arrive */
-		if (SG_IS_DETACHING(sdp)) {
-			ret = -ENODEV;
-			goto free_old_hdr;
-		}
-		if (filp->f_flags & O_NONBLOCK) {
-			ret = -EAGAIN;
-			goto free_old_hdr;
-		}
-		ret = wait_event_interruptible
-				(sfp->read_wait,
-				 (SG_IS_DETACHING(sdp) ||
-				  (srp = sg_get_rq_mark(sfp, req_pack_id))));
-		if (SG_IS_DETACHING(sdp)) {
-			ret = -ENODEV;
-			goto free_old_hdr;
-		}
-		if (ret) {
-			/* -ERESTARTSYS as signal hit process */
-			goto free_old_hdr;
-		}
-	}
-	if (srp->header.interface_id != '\0') {
-		ret = sg_new_read(sfp, buf, count, srp);
-		goto free_old_hdr;
-	}
-
-	hp = &srp->header;
-	if (old_hdr == NULL) {
-		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
-		if (!old_hdr) {
-			ret = -ENOMEM;
-			goto free_old_hdr;
-		}
-	}
-	memset(old_hdr, 0, SZ_SG_HEADER);
-	old_hdr->reply_len = (int) hp->timeout;
-	old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
-	old_hdr->pack_id = hp->pack_id;
-	old_hdr->twelve_byte =
-	    ((srp->data.cmd_opcode >= 0xc0) && (hp->cmd_len == 12)) ? 1 : 0;
-	old_hdr->target_status = hp->masked_status;
-	old_hdr->host_status = hp->host_status;
-	old_hdr->driver_status = hp->driver_status;
-	if ((hp->masked_status & CHECK_CONDITION) ||
-	    (hp->driver_status & DRIVER_SENSE))
-		memcpy(old_hdr->sense_buffer, srp->sense_b,
-		       sizeof(old_hdr->sense_buffer));
-	switch (hp->host_status) {
+	int res = 0;
+	struct sg_io_hdr *sh3p = &srp->header;
+	struct sg_header *h2p;
+	struct sg_header a_v2hdr;
+
+	h2p = &a_v2hdr;
+	memset(h2p, 0, SZ_SG_HEADER);
+	h2p->reply_len = (int)sh3p->timeout;
+	h2p->pack_len = h2p->reply_len; /* old, strange behaviour */
+	h2p->pack_id = sh3p->pack_id;
+	h2p->twelve_byte = (srp->data.cmd_opcode >= 0xc0 &&
+			    sh3p->cmd_len == 12);
+	h2p->target_status = sh3p->masked_status;
+	h2p->host_status = sh3p->host_status;
+	h2p->driver_status = sh3p->driver_status;
+	if ((CHECK_CONDITION & h2p->target_status) ||
+	    (DRIVER_SENSE & sh3p->driver_status)) {
+		memcpy(h2p->sense_buffer, srp->sense_b,
+		       sizeof(h2p->sense_buffer));
+	}
+	switch (h2p->host_status) {
 	/*
-	 * This setup of 'result' is for backward compatibility and is best
-	 * ignored by the user who should use target, host + driver status
+	 * This foolowing setting of 'result' is for backward compatibility
+	 * and is best ignored by the user who should use target, host and
+	 * driver status.
 	 */
 	case DID_OK:
 	case DID_PASSTHROUGH:
 	case DID_SOFT_ERROR:
-		old_hdr->result = 0;
+		h2p->result = 0;
 		break;
 	case DID_NO_CONNECT:
 	case DID_BUS_BUSY:
 	case DID_TIME_OUT:
-		old_hdr->result = EBUSY;
+		h2p->result = EBUSY;
 		break;
 	case DID_BAD_TARGET:
 	case DID_ABORT:
 	case DID_PARITY:
 	case DID_RESET:
 	case DID_BAD_INTR:
-		old_hdr->result = EIO;
+		h2p->result = EIO;
 		break;
 	case DID_ERROR:
-		old_hdr->result = (srp->sense_b[0] == 0 &&
-				  hp->masked_status == GOOD) ? 0 : EIO;
+		h2p->result = (h2p->target_status == GOOD) ? 0 : EIO;
 		break;
 	default:
-		old_hdr->result = EIO;
+		h2p->result = EIO;
 		break;
 	}
 
 	/* Now copy the result back to the user buffer.  */
 	if (count >= SZ_SG_HEADER) {
-		if (copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
-			ret = -EFAULT;
-			goto free_old_hdr;
-		}
+		if (copy_to_user(buf, h2p, SZ_SG_HEADER))
+			return -EFAULT;
 		buf += SZ_SG_HEADER;
-		if (count > old_hdr->reply_len)
-			count = old_hdr->reply_len;
+		if (count > h2p->reply_len)
+			count = h2p->reply_len;
 		if (count > SZ_SG_HEADER) {
-			if (sg_rd_append(srp, buf, count - SZ_SG_HEADER)) {
-				ret = -EFAULT;
-				goto free_old_hdr;
-			}
+			if (sg_rd_append(srp, buf, count - SZ_SG_HEADER))
+				return -EFAULT;
 		}
 	} else
-		count = (old_hdr->result == 0) ? 0 : -EIO;
+		res = (h2p->result == 0) ? 0 : -EIO;
 	sg_finish_scsi_blk_rq(srp);
 	sg_remove_request(sfp, srp);
-	ret = count;
-free_old_hdr:
-	kfree(old_hdr);
-	return ret;
+	return res;
+}
+
+static ssize_t
+sg_read(struct file *filp, char __user *p, size_t count, loff_t *ppos)
+{
+	bool could_be_v3;
+	bool non_block = !!(filp->f_flags & O_NONBLOCK);
+	int want_id = -1;
+	int hlen, ret;
+	struct sg_device *sdp;
+	struct sg_fd *sfp;
+	struct sg_request *srp;
+	struct sg_header *h2p = NULL;
+	struct sg_io_hdr a_sg_io_hdr;
+
+	/*
+	 * This could cause a response to be stranded. Close the associated
+	 * file descriptor to free up any resources being held.
+	 */
+	ret = sg_check_file_access(filp, __func__);
+	if (ret)
+		return ret;
+
+	sfp = filp->private_data;
+	sdp = sfp->parentdp;
+	SG_LOG(3, sfp, "%s: read() count=%d\n", __func__, (int)count);
+	ret = sg_allow_if_err_recovery(sdp, false);
+	if (ret)
+		return ret;
+
+	could_be_v3 = (count >= SZ_SG_IO_HDR);
+	hlen = could_be_v3 ? SZ_SG_IO_HDR : SZ_SG_HEADER;
+	h2p = (struct sg_header *)&a_sg_io_hdr;
+
+	if (sfp->force_packid && count >= hlen) {
+		/*
+		 * Even though this is a user space read() system call, this
+		 * code is cheating to fetch the pack_id.
+		 * Only need first three 32 bit ints to determine interface.
+		 */
+		if (unlikely(copy_from_user(h2p, p, 3 * sizeof(int))))
+			return -EFAULT;
+		if (h2p->reply_len < 0 && could_be_v3) {
+			struct sg_io_hdr *v3_hdr = (struct sg_io_hdr *)h2p;
+
+			if (likely(v3_hdr->interface_id == 'S')) {
+				struct sg_io_hdr __user *h3_up;
+
+				h3_up = (struct sg_io_hdr __user *)p;
+				ret = get_user(want_id, &h3_up->pack_id);
+				if (unlikely(ret))
+					return ret;
+			} else if (v3_hdr->interface_id == 'Q') {
+				pr_info_once("sg: %s: v4 interface%s here\n",
+					     __func__, " disallowed");
+				return -EPERM;
+			} else {
+				return -EPERM;
+			}
+		} else { /* for v1+v2 interfaces, this is the 3rd integer */
+			want_id = h2p->pack_id;
+		}
+	}
+	srp = sg_get_rq_mark(sfp, want_id);
+	if (!srp) {		/* now wait on packet to arrive */
+		if (SG_IS_DETACHING(sdp))
+			return -ENODEV;
+		if (non_block) /* O_NONBLOCK or v3::flags & SGV4_FLAG_IMMED */
+			return -EAGAIN;
+		ret = wait_event_interruptible
+				(sfp->read_wait,
+				 (SG_IS_DETACHING(sdp) ||
+				  (srp = sg_get_rq_mark(sfp, want_id))));
+		if (SG_IS_DETACHING(sdp))
+			return -ENODEV;
+		if (ret)	/* -ERESTARTSYS as signal hit process */
+			return ret;
+	}
+	if (srp->header.interface_id == '\0') {
+		ret = sg_rd_v1v2(p, (int)count, sfp, srp);
+	} else {
+		if ((int)count < SZ_SG_IO_HDR)
+			return -EINVAL;
+		ret = sg_v3_receive(sfp, p, srp);
+	}
+	if (ret < 0)
+		SG_LOG(1, sfp, "%s: negated errno: %d\n", __func__, ret);
+	return ret < 0 ? ret : (int)count;
 }
 
 static int
@@ -1043,7 +1040,7 @@ sg_ctl_sg_io(struct file *filp, struct sg_device *sdp, struct sg_fd *sfp,
 	if (srp->done) {
 		srp->done = 2;
 		spin_unlock_irq(&sfp->rq_list_lock);
-		res = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
+		res = sg_v3_receive(sfp, p, srp);
 		return (res < 0) ? res : 0;
 	}
 	srp->orphan = 1;
-- 
2.23.0


  parent reply	other threads:[~2019-10-08  7:50 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-08  7:49 [PATCH v5 00/23] sg: add v4 interface Douglas Gilbert
2019-10-08  7:50 ` [PATCH v5 01/23] sg: move functions around Douglas Gilbert
2019-10-08  7:50 ` [PATCH v5 02/23] sg: remove typedefs, type+formatting cleanup Douglas Gilbert
2019-10-08  7:50 ` [PATCH v5 03/23] sg: sg_log and is_enabled Douglas Gilbert
2019-10-08  7:50 ` [PATCH v5 04/23] sg: rework sg_poll(), minor changes Douglas Gilbert
2019-10-08  7:50 ` [PATCH v5 05/23] sg: bitops in sg_device Douglas Gilbert
2019-10-18 10:05   ` Hannes Reinecke
2019-10-21 13:22     ` Douglas Gilbert
2019-10-21 13:38       ` Hannes Reinecke
2019-10-08  7:50 ` [PATCH v5 06/23] sg: make open count an atomic Douglas Gilbert
2019-10-08  7:50 ` [PATCH v5 07/23] sg: move header to uapi section Douglas Gilbert
2019-10-08  7:50 ` [PATCH v5 08/23] sg: speed sg_poll and sg_get_num_waiting Douglas Gilbert
2019-10-08  7:50 ` [PATCH v5 09/23] sg: sg_allow_if_err_recovery and renames Douglas Gilbert
2019-10-08  7:50 ` [PATCH v5 10/23] sg: remove access_ok functions Douglas Gilbert
2019-10-08  7:50 ` [PATCH v5 11/23] sg: improve naming Douglas Gilbert
2019-10-18 10:06   ` Hannes Reinecke
2019-10-08  7:50 ` [PATCH v5 12/23] sg: change rwlock to spinlock Douglas Gilbert
2019-10-18 10:09   ` Hannes Reinecke
2019-10-08  7:50 ` [PATCH v5 13/23] sg: ioctl handling Douglas Gilbert
2019-10-18 10:12   ` Hannes Reinecke
2019-10-24  2:47     ` Douglas Gilbert
2019-10-08  7:50 ` Douglas Gilbert [this message]
2019-10-18 10:15   ` [PATCH v5 14/23] sg: split sg_read Hannes Reinecke
2019-10-08  7:50 ` [PATCH v5 15/23] sg: sg_common_write add structure for arguments Douglas Gilbert
2019-10-18 10:16   ` Hannes Reinecke
2019-10-08  7:50 ` [PATCH v5 16/23] sg: rework sg_vma_fault Douglas Gilbert
2019-10-18 10:17   ` Hannes Reinecke
2019-10-24  3:07     ` Douglas Gilbert
2019-10-08  7:50 ` [PATCH v5 17/23] sg: rework sg_mmap Douglas Gilbert
2019-10-18 10:18   ` Hannes Reinecke
2019-10-08  7:50 ` [PATCH v5 18/23] sg: replace sg_allow_access Douglas Gilbert
2019-10-18 10:20   ` Hannes Reinecke
2019-10-08  7:50 ` [PATCH v5 19/23] sg: rework scatter gather handling Douglas Gilbert
2019-10-18 10:22   ` Hannes Reinecke
2019-10-08  7:50 ` [PATCH v5 20/23] sg: introduce request state machine Douglas Gilbert
2019-10-18 10:25   ` Hannes Reinecke
2019-10-24  4:24     ` Douglas Gilbert
2019-10-24  5:51       ` Hannes Reinecke
2019-10-08  7:50 ` [PATCH v5 21/23] sg: sg_find_srp_by_id Douglas Gilbert
2019-10-18 10:27   ` Hannes Reinecke
2019-10-08  7:50 ` [PATCH v5 22/23] sg: sg_fill_request_element Douglas Gilbert
2019-10-18 10:29   ` Hannes Reinecke
2019-10-08  7:50 ` [PATCH v5 23/23] sg: printk change %p to %pK Douglas Gilbert

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191008075022.30055-15-dgilbert@interlog.com \
    --to=dgilbert@interlog.com \
    --cc=hare@suse.de \
    --cc=jejb@linux.vnet.ibm.com \
    --cc=linux-scsi@vger.kernel.org \
    --cc=martin.petersen@oracle.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.