From: Chad Dupuis <chad.dupuis@qlogic.com>
To: linux-scsi@vger.kernel.org
Cc: fujita.tomonori@lab.ntt.co.jp
Subject: [RFC v3 PATCH 1/2] bsg: Add infrastructure to send in kernel bsg commands.
Date: Thu, 16 Jun 2011 08:36:19 -0400 [thread overview]
Message-ID: <alpine.LFD.2.02.1106160825540.2424@localhost.localdomain> (raw)
This is version 3 of this patch which is based on review comments here:
http://marc.info/?l=linux-scsi&m=130590738308822&w=2
Essentially, the code was refactored to reduce code duplication.
From: Chad Dupuis <chad.dupuis@qlogic.com>
This patch adds a new exported function, bsg_private_command() that allows a
device driver or other kernel code to be able to send bsg commands from within
the kernel using sg_io_v4. The private command infrastructure mimics the ioctl
interface except that the bsg request queue needs to be explicitly passed in.
bsg_map_hdr() and blk_fill_sgv4_hdr_rq() needed to be refactored slightly as
well to allow for both user and kernel buffers. Two helper functions were
created as a front-end to bsg_map_hdr() so as to call bsg_map_hdr() with the correct
semantics depending on the type of buffer that we're using. bsg_map_hdr() and
blk_fill_sgv4_hdr_rq() also have an extra argument, is_user, to tell what type
of buffer is being used as well.
Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
---
block/bsg.c | 138 ++++++++++++++++++++++++++++++++++++++++-----------
include/linux/bsg.h | 1 +
2 files changed, 109 insertions(+), 30 deletions(-)
diff --git a/block/bsg.c b/block/bsg.c
index 0c8b64a..9babd96 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -74,6 +74,8 @@ static int bsg_major;
static struct kmem_cache *bsg_cmd_cachep;
+static struct request *
+bsg_map_hdr(struct request_queue *, struct sg_io_v4 *, fmode_t, u8 *, int);
/*
* our internal command type
*/
@@ -173,8 +175,8 @@ unlock:
}
static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
- struct sg_io_v4 *hdr, struct bsg_device *bd,
- fmode_t has_write_perm)
+ struct sg_io_v4 *hdr, fmode_t has_write_perm,
+ int is_user)
{
if (hdr->request_len > BLK_MAX_CDB) {
rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL);
@@ -182,9 +184,14 @@ static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
return -ENOMEM;
}
- if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request,
- hdr->request_len))
- return -EFAULT;
+ if (is_user) {
+ if (copy_from_user(rq->cmd,
+ (void *)(unsigned long)hdr->request, hdr->request_len))
+ return -EFAULT;
+ } else {
+ memcpy(rq->cmd, (void *)(unsigned long)hdr->request,
+ hdr->request_len);
+ }
if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) {
if (blk_verify_command(rq->cmd, has_write_perm))
@@ -238,18 +245,13 @@ bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw)
return ret;
}
-/*
- * map sg_io_v4 to a request.
- */
+#define BSG_BUFFER_KERN 0
+#define BSG_BUFFER_USER 1
static struct request *
-bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm,
- u8 *sense)
+bsg_map_hdr_user(struct bsg_device *bd, struct sg_io_v4 *hdr,
+ fmode_t has_write_perm, u8 *sense)
{
struct request_queue *q = bd->queue;
- struct request *rq, *next_rq = NULL;
- int ret, rw;
- unsigned int dxfer_len;
- void *dxferp = NULL;
struct bsg_class_device *bcd = &q->bsg_dev;
/* if the LLD has been removed then the bsg_unregister_queue will
@@ -259,6 +261,28 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm,
if (!bcd->class_dev)
return ERR_PTR(-ENXIO);
+ return(bsg_map_hdr(q, hdr, has_write_perm, sense, BSG_BUFFER_USER));
+}
+
+static struct request *
+bsg_map_hdr_kern(struct request_queue *q, struct sg_io_v4 *hdr,
+ fmode_t has_write_perm, u8 *sense)
+{
+ return(bsg_map_hdr(q, hdr, has_write_perm, sense, BSG_BUFFER_KERN));
+}
+
+/*
+ * map sg_io_v4 to a request.
+ */
+static struct request *
+bsg_map_hdr(struct request_queue *q, struct sg_io_v4 *hdr,
+ fmode_t has_write_perm, u8 *sense, int is_user)
+{
+ struct request *rq, *next_rq = NULL;
+ int ret, rw;
+ unsigned int dxfer_len;
+ void *dxferp = NULL;
+
dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp,
hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp,
hdr->din_xfer_len);
@@ -273,7 +297,7 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm,
rq = blk_get_request(q, rw, GFP_KERNEL);
if (!rq)
return ERR_PTR(-ENOMEM);
- ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm);
+ ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, has_write_perm, is_user);
if (ret)
goto out;
@@ -292,8 +316,14 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm,
next_rq->cmd_type = rq->cmd_type;
dxferp = (void*)(unsigned long)hdr->din_xferp;
- ret = blk_rq_map_user(q, next_rq, NULL, dxferp,
- hdr->din_xfer_len, GFP_KERNEL);
+
+ if (is_user)
+ ret = blk_rq_map_user(q, next_rq, NULL, dxferp,
+ hdr->din_xfer_len, GFP_KERNEL);
+ else
+ ret = blk_rq_map_kern(q, next_rq, dxferp,
+ hdr->din_xfer_len, GFP_KERNEL);
+
if (ret)
goto out;
}
@@ -308,8 +338,13 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm,
dxfer_len = 0;
if (dxfer_len) {
- ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len,
- GFP_KERNEL);
+ if (is_user)
+ ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len,
+ GFP_KERNEL);
+ else
+ ret = blk_rq_map_kern(q, rq, dxferp, dxfer_len,
+ GFP_KERNEL);
+
if (ret)
goto out;
}
@@ -323,7 +358,8 @@ out:
kfree(rq->cmd);
blk_put_request(rq);
if (next_rq) {
- blk_rq_unmap_user(next_rq->bio);
+ if (is_user)
+ blk_rq_unmap_user(next_rq->bio);
blk_put_request(next_rq);
}
return ERR_PTR(ret);
@@ -425,7 +461,8 @@ static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd)
}
static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
- struct bio *bio, struct bio *bidi_bio)
+ struct bio *bio, struct bio *bidi_bio,
+ int is_user)
{
int ret = 0;
@@ -445,8 +482,13 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
int len = min_t(unsigned int, hdr->max_response_len,
rq->sense_len);
- ret = copy_to_user((void*)(unsigned long)hdr->response,
- rq->sense, len);
+ if (is_user)
+ ret = copy_to_user((void*)(unsigned long)hdr->response,
+ rq->sense, len);
+ else
+ memcpy((void*)(unsigned long)hdr->response, rq->sense,
+ len);
+
if (!ret)
hdr->response_len = len;
else
@@ -456,7 +498,8 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
if (rq->next_rq) {
hdr->dout_resid = rq->resid_len;
hdr->din_resid = rq->next_rq->resid_len;
- blk_rq_unmap_user(bidi_bio);
+ if (is_user)
+ blk_rq_unmap_user(bidi_bio);
blk_put_request(rq->next_rq);
} else if (rq_data_dir(rq) == READ)
hdr->din_resid = rq->resid_len;
@@ -472,7 +515,8 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
if (!ret && rq->errors < 0)
ret = rq->errors;
- blk_rq_unmap_user(bio);
+ if (is_user)
+ blk_rq_unmap_user(bio);
if (rq->cmd != rq->__cmd)
kfree(rq->cmd);
blk_put_request(rq);
@@ -519,7 +563,7 @@ static int bsg_complete_all_commands(struct bsg_device *bd)
break;
tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
- bc->bidi_bio);
+ bc->bidi_bio, 1);
if (!ret)
ret = tret;
@@ -554,7 +598,7 @@ __bsg_read(char __user *buf, size_t count, struct bsg_device *bd,
* bsg_complete_work() cannot do that for us
*/
ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
- bc->bidi_bio);
+ bc->bidi_bio, 1);
if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr)))
ret = -EFAULT;
@@ -645,7 +689,7 @@ static int __bsg_write(struct bsg_device *bd, const char __user *buf,
/*
* get a request, fill in the blanks, and add to request queue
*/
- rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm, bc->sense);
+ rq = bsg_map_hdr_user(bd, &bc->hdr, has_write_perm, bc->sense);
if (IS_ERR(rq)) {
ret = PTR_ERR(rq);
rq = NULL;
@@ -936,7 +980,7 @@ static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
if (copy_from_user(&hdr, uarg, sizeof(hdr)))
return -EFAULT;
- rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE, sense);
+ rq = bsg_map_hdr_user(bd, &hdr, file->f_mode & FMODE_WRITE, sense);
if (IS_ERR(rq))
return PTR_ERR(rq);
@@ -946,7 +990,7 @@ static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL));
blk_execute_rq(bd->queue, NULL, rq, at_head);
- ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio);
+ ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio, 1);
if (copy_to_user(uarg, &hdr, sizeof(hdr)))
return -EFAULT;
@@ -965,6 +1009,40 @@ static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
}
}
+int bsg_private_command (struct request_queue *q, struct sg_io_v4 *hdr)
+{
+ struct request *rq;
+ struct bio *bio, *bidi_bio = NULL;
+ int at_head;
+ u8 sense[SCSI_SENSE_BUFFERSIZE];
+ fmode_t has_write_perm = 0;
+ int ret;
+
+ if (!q)
+ return -ENXIO;
+
+ /* Fake that we have write permission */
+ has_write_perm |= FMODE_WRITE;
+
+ rq = bsg_map_hdr_kern(q, hdr, has_write_perm, sense);
+
+ if (IS_ERR(rq)) {
+ return PTR_ERR(rq);
+ }
+
+ bio = rq->bio;
+ if (rq->next_rq)
+ bidi_bio = rq->next_rq->bio;
+
+ at_head = (0 == (hdr->flags & BSG_FLAG_Q_AT_TAIL));
+
+ blk_execute_rq(q, NULL, rq, at_head);
+ ret = blk_complete_sgv4_hdr_rq(rq, hdr, bio, bidi_bio, 0);
+
+ return ret;
+}
+EXPORT_SYMBOL(bsg_private_command);
+
static const struct file_operations bsg_fops = {
.read = bsg_read,
.write = bsg_write,
diff --git a/include/linux/bsg.h b/include/linux/bsg.h
index ecb4730..60adc01 100644
--- a/include/linux/bsg.h
+++ b/include/linux/bsg.h
@@ -77,6 +77,7 @@ extern int bsg_register_queue(struct request_queue *q,
struct device *parent, const char *name,
void (*release)(struct device *));
extern void bsg_unregister_queue(struct request_queue *);
+extern int bsg_private_command (struct request_queue *, struct sg_io_v4 *);
#else
static inline int bsg_register_queue(struct request_queue *q,
struct device *parent, const char *name,
--
1.7.0.31.g1df487
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next reply other threads:[~2011-06-16 12:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-16 12:36 Chad Dupuis [this message]
2011-06-23 1:51 ` [RFC v3 PATCH 1/2] bsg: Add infrastructure to send in kernel bsg commands FUJITA Tomonori
2011-06-24 2:02 ` Boaz Harrosh
2011-06-29 7:11 ` FUJITA Tomonori
2011-06-29 20:27 ` Chad Dupuis
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