Expose possible userland flags to the new PI IO extension so that
userspace can discover what flags exist.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-block | 14 ++++++++++++++
Documentation/block/data-integrity.txt | 22 +++++++++++++++++++++
block/blk-integrity.c | 33 ++++++++++++++++++++++++++++++++
drivers/scsi/sd_dif.c | 11 +++++++++++
include/linux/blkdev.h | 7 +++++++
5 files changed, 87 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block
index 279da08..989cb80 100644
--- a/Documentation/ABI/testing/sysfs-block
+++ b/Documentation/ABI/testing/sysfs-block
@@ -53,6 +53,20 @@ Description:
512 bytes of data.
+What: /sys/block/<disk>/integrity/tuple_size
+Date: March 2014
+Contact: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
+Description:
+ Size in bytes of the integrity data buffer for each logical
+ block.
+
+What: /sys/block/<disk>/integrity/write_user_flags
+Date: March 2014
+Contact: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
+Description:
+ Provides a list of flags that userspace can pass to the kernel
+ when supplying integrity data for a write IO.
+
What: /sys/block/<disk>/integrity/write_generate
Date: June 2008
Contact: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
diff --git a/Documentation/block/data-integrity.txt b/Documentation/block/data-integrity.txt
index b72a54f..e33d4a7 100644
--- a/Documentation/block/data-integrity.txt
+++ b/Documentation/block/data-integrity.txt
@@ -341,7 +341,29 @@ will require extra work due to the application tag.
specific to the blk_integrity provider) arrange for pre-processing
of the user buffer prior to issuing the IO.
+ 'user_write_flags' points to an array of struct blk_integrity_flag,
+ which maps mod_user_buf_fn flags to a description of what they do.
+
See 6.2 for a description of get_tag_fn and set_tag_fn.
+5.5 PASSING INTEGRITY DATA FROM USERSPACE
+
+ The "IO extension" interface has been expanded to provide
+ userspace programs with the ability to provide PI data with a WRITE,
+ or to receive PI data with a READ. The fields ie_pi_buf,
+ ie_pi_buflen, and ie_pi_flags should contain a pointer to the PI
+ buffer, the length of the PI buffer, and any flags that should be
+ passed to the PI provider.
+
+ This buffer must contain PI tuples. Tuples must NOT split a page
+ boundary. Valid flag values can be found in
+ /sys/block/*/integrity/user_write_flags. The tuple size can be found
+ in /sys/block/*/integrity/tuple_size.
+
+ In general, the flags allow the user program to ask the in-kernel
+ integrity provider to fill in some parts of the tuples. For example,
+ the T10 DIF provider can fill in the reference tag (sector number) so
+ that userspace can choose not to care about the reference tag.
+
----------------------------------------------------------------------
2007-12-24 Martin K. Petersen <martin.petersen@xxxxxxxxxx>
diff --git a/block/blk-integrity.c b/block/blk-integrity.c
index 1cb1eb2..557d28e 100644
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -307,6 +307,26 @@ static ssize_t integrity_write_show(struct blk_integrity *bi, char *page)
return sprintf(page, "%d\n", (bi->flags & INTEGRITY_FLAG_WRITE) != 0);
}
+static ssize_t integrity_write_flags_show(struct blk_integrity *bi, char *page)
+{
+ struct blk_integrity_flag *flag = bi->user_write_flags;
+ char *p = page;
+ ssize_t ret = 0;
+
+ while (flag->value) {
+ ret += snprintf(p, PAGE_SIZE - ret, "0x%x: %s\n",
+ flag->value, flag->descr);
+ p = page + ret;
+ flag++;
+ }
+ return ret;
+}
+
+static ssize_t integrity_tuple_size_show(struct blk_integrity *bi, char *page)
+{
+ return sprintf(page, "%d\n", bi->tuple_size);
+}
+
static struct integrity_sysfs_entry integrity_format_entry = {
.attr = { .name = "format", .mode = S_IRUGO },
.show = integrity_format_show,
@@ -329,11 +349,23 @@ static struct integrity_sysfs_entry integrity_write_entry = {
.store = integrity_write_store,
};
+static struct integrity_sysfs_entry integrity_write_flags_entry = {
+ .attr = { .name = "write_user_flags", .mode = S_IRUGO },
+ .show = integrity_write_flags_show,
+};
+
+static struct integrity_sysfs_entry integrity_tuple_size_entry = {
+ .attr = { .name = "tuple_size", .mode = S_IRUGO },
+ .show = integrity_tuple_size_show,
+};
+
static struct attribute *integrity_attrs[] = {
&integrity_format_entry.attr,
&integrity_tag_size_entry.attr,
&integrity_read_entry.attr,
&integrity_write_entry.attr,
+ &integrity_write_flags_entry.attr,
+ &integrity_tuple_size_entry.attr,
NULL,
};
@@ -422,6 +454,7 @@ int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
bi->get_tag_fn = template->get_tag_fn;
bi->tag_size = template->tag_size;
bi->mod_user_buf_fn = template->mod_user_buf_fn;
+ bi->user_write_flags = template->user_write_flags;
} else
bi->name = bi_unsupported_name;
diff --git a/drivers/scsi/sd_dif.c b/drivers/scsi/sd_dif.c
index 74182c9..bea648b 100644
--- a/drivers/scsi/sd_dif.c
+++ b/drivers/scsi/sd_dif.c
@@ -182,6 +182,13 @@ static void sd_dif_type1_get_tag(void *prot, void *tag_buf, unsigned int sectors
}
}
+static struct blk_integrity_flag dif_flags[] = {
+ {GENERATE_GUARD, "generate guard tag"},
+ {GENERATE_REF, "generate ref tag"},
+ {GENERATE_APP, "generate app tag"},
+ {0, NULL},
+};
+
static struct blk_integrity dif_type1_integrity_crc = {
.name = "T10-DIF-TYPE1-CRC",
.generate_fn = sd_dif_type1_generate_crc,
@@ -191,6 +198,7 @@ static struct blk_integrity dif_type1_integrity_crc = {
.tuple_size = sizeof(struct sd_dif_tuple),
.tag_size = 0,
.mod_user_buf_fn = sd_dif_type1_mod_crc,
+ .user_write_flags = dif_flags,
};
static struct blk_integrity dif_type1_integrity_ip = {
@@ -202,6 +210,7 @@ static struct blk_integrity dif_type1_integrity_ip = {
.tuple_size = sizeof(struct sd_dif_tuple),
.tag_size = 0,
.mod_user_buf_fn = sd_dif_type1_mod_ip,
+ .user_write_flags = dif_flags,
};
@@ -334,6 +343,7 @@ static struct blk_integrity dif_type3_integrity_crc = {
.tuple_size = sizeof(struct sd_dif_tuple),
.tag_size = 0,
.mod_user_buf_fn = sd_dif_type3_mod_crc,
+ .user_write_flags = dif_flags,
};
static struct blk_integrity dif_type3_integrity_ip = {
@@ -345,6 +355,7 @@ static struct blk_integrity dif_type3_integrity_ip = {
.tuple_size = sizeof(struct sd_dif_tuple),
.tag_size = 0,
.mod_user_buf_fn = sd_dif_type3_mod_ip,
+ .user_write_flags = dif_flags,
};
/*
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index cf1ec22..e8e6401 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1428,6 +1428,11 @@ typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
typedef int (integrity_mod_user_buf_fn) (struct blk_integrity_exchg *, int);
+struct blk_integrity_flag {
+ unsigned int value;
+ const char *descr;
+};
+
struct blk_integrity {
integrity_gen_fn *generate_fn;
integrity_vrfy_fn *verify_fn;
@@ -1443,6 +1448,8 @@ struct blk_integrity {
const char *name;
struct kobject kobj;
+
+ struct blk_integrity_flag *user_write_flags;
};
extern bool blk_integrity_is_initialized(struct gendisk *);
--
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