Re: [PATCH-v2 12/17] target/file: Add DIF protection init/formatsupport
From: Sagi Grimberg
Date: Sun Jan 19 2014 - 07:31:25 EST
On 1/19/2014 4:44 AM, Nicholas A. Bellinger wrote:
From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This patch adds support for DIF protection init/format support into
the FILEIO backend.
It involves using a seperate $FILE.protection for storing PI that is
opened via fd_init_prot() using the common pi_prot_type attribute.
The actual formatting of the protection is done via fd_format_prot()
using the common pi_prot_format attribute, that will populate the
initial PI data based upon the currently configured pi_prot_type.
Based on original FILEIO code from Sagi.
Nice! see comments below...
v1 changes:
- Fix sparse warnings in fd_init_format_buf (Fengguang)
Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx>
Cc: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_file.c | 137 +++++++++++++++++++++++++++++++++++++
drivers/target/target_core_file.h | 4 ++
2 files changed, 141 insertions(+)
diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c
index 0e34cda..119d519 100644
--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c
@@ -700,6 +700,140 @@ static sector_t fd_get_blocks(struct se_device *dev)
dev->dev_attrib.block_size);
}
+static int fd_init_prot(struct se_device *dev)
+{
+ struct fd_dev *fd_dev = FD_DEV(dev);
+ struct file *prot_file, *file = fd_dev->fd_file;
+ struct inode *inode;
+ int ret, flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;
+ char buf[FD_MAX_DEV_PROT_NAME];
+
+ if (!file) {
+ pr_err("Unable to locate fd_dev->fd_file\n");
+ return -ENODEV;
+ }
+
+ inode = file->f_mapping->host;
+ if (S_ISBLK(inode->i_mode)) {
+ pr_err("FILEIO Protection emulation only supported on"
+ " !S_ISBLK\n");
+ return -ENOSYS;
+ }
+
+ if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE)
+ flags &= ~O_DSYNC;
+
+ snprintf(buf, FD_MAX_DEV_PROT_NAME, "%s.protection",
+ fd_dev->fd_dev_name);
+
+ prot_file = filp_open(buf, flags, 0600);
+ if (IS_ERR(prot_file)) {
+ pr_err("filp_open(%s) failed\n", buf);
+ ret = PTR_ERR(prot_file);
+ return ret;
+ }
+ fd_dev->fd_prot_file = prot_file;
+
+ return 0;
+}
+
+static void fd_init_format_buf(struct se_device *dev, unsigned char *buf,
+ u32 unit_size, u32 *ref_tag, u16 app_tag,
+ bool inc_reftag)
+{
+ unsigned char *p = buf;
+ int i;
+
+ for (i = 0; i < unit_size; i += dev->prot_length) {
+ *((u16 *)&p[0]) = 0xffff;
+ *((__be16 *)&p[2]) = cpu_to_be16(app_tag);
+ *((__be32 *)&p[4]) = cpu_to_be32(*ref_tag);
+
+ if (inc_reftag)
+ (*ref_tag)++;
+
+ p += dev->prot_length;
+ }
+}
+
+static int fd_format_prot(struct se_device *dev)
+{
+ struct fd_dev *fd_dev = FD_DEV(dev);
+ struct file *prot_fd = fd_dev->fd_prot_file;
+ sector_t prot_length, prot;
+ unsigned char *buf;
+ loff_t pos = 0;
+ u32 ref_tag = 0;
+ int unit_size = FDBD_FORMAT_UNIT_SIZE * dev->dev_attrib.block_size;
+ int rc, ret = 0, size, len;
+ bool inc_reftag = false;
+
+ if (!dev->dev_attrib.pi_prot_type) {
+ pr_err("Unable to format_prot while pi_prot_type == 0\n");
+ return -ENODEV;
+ }
+ if (!prot_fd) {
+ pr_err("Unable to locate fd_dev->fd_prot_file\n");
+ return -ENODEV;
+ }
+
+ switch (dev->dev_attrib.pi_prot_type) {
redundant - see below.
+ case TARGET_DIF_TYPE3_PROT:
+ ref_tag = 0xffffffff;
+ break;
+ case TARGET_DIF_TYPE2_PROT:
+ case TARGET_DIF_TYPE1_PROT:
+ inc_reftag = true;
+ break;
+ default:
+ break;
+ }
+
+ buf = vzalloc(unit_size);
+ if (!buf) {
+ pr_err("Unable to allocate FILEIO prot buf\n");
+ return -ENOMEM;
+ }
+
+ prot_length = (dev->transport->get_blocks(dev) + 1) * dev->prot_length;
+ size = prot_length;
+
+ pr_debug("Using FILEIO prot_length: %llu\n",
+ (unsigned long long)prot_length);
+
+ for (prot = 0; prot < prot_length; prot += unit_size) {
+
+ fd_init_format_buf(dev, buf, unit_size, &ref_tag, 0xffff,
+ inc_reftag);
I didn't send you my latest patches (my fault...).T10-PI format should
only place
escape values throughout the protection file (fill it with 0xff). so I
guess in this case
fd_init_formast_buf() boils down to memset(buf, 0xff, unit_size) once
before the loop
and just loop until prot_length writing buf, no need to address
apptag/reftag...
+
+ len = min(unit_size, size);
+
+ rc = kernel_write(prot_fd, buf, len, pos);
+ if (rc != len) {
+ pr_err("vfs_write to prot file failed: %d\n", rc);
+ ret = -ENODEV;
+ goto out;
+ }
+ pos += len;
+ size -= len;
+ }
+
+out:
+ vfree(buf);
+ return ret;
+}
+
+static void fd_free_prot(struct se_device *dev)
+{
+ struct fd_dev *fd_dev = FD_DEV(dev);
+
+ if (!fd_dev->fd_prot_file)
+ return;
+
+ filp_close(fd_dev->fd_prot_file, NULL);
+ fd_dev->fd_prot_file = NULL;
+}
+
static struct sbc_ops fd_sbc_ops = {
.execute_rw = fd_execute_rw,
.execute_sync_cache = fd_execute_sync_cache,
@@ -730,6 +864,9 @@ static struct se_subsystem_api fileio_template = {
.show_configfs_dev_params = fd_show_configfs_dev_params,
.get_device_type = sbc_get_device_type,
.get_blocks = fd_get_blocks,
+ .init_prot = fd_init_prot,
+ .format_prot = fd_format_prot,
+ .free_prot = fd_free_prot,
};
static int __init fileio_module_init(void)
diff --git a/drivers/target/target_core_file.h b/drivers/target/target_core_file.h
index 37ffc5b..583691e 100644
--- a/drivers/target/target_core_file.h
+++ b/drivers/target/target_core_file.h
@@ -4,6 +4,7 @@
#define FD_VERSION "4.0"
#define FD_MAX_DEV_NAME 256
+#define FD_MAX_DEV_PROT_NAME FD_MAX_DEV_NAME + 16
#define FD_DEVICE_QUEUE_DEPTH 32
#define FD_MAX_DEVICE_QUEUE_DEPTH 128
#define FD_BLOCKSIZE 512
@@ -15,6 +16,8 @@
#define FBDF_HAS_PATH 0x01
#define FBDF_HAS_SIZE 0x02
#define FDBD_HAS_BUFFERED_IO_WCE 0x04
+#define FDBD_FORMAT_UNIT_SIZE 2048
+
struct fd_dev {
struct se_device dev;
@@ -29,6 +32,7 @@ struct fd_dev {
u32 fd_block_size;
unsigned long long fd_dev_size;
struct file *fd_file;
+ struct file *fd_prot_file;
/* FILEIO HBA device is connected to */
struct fd_host *fd_host;
} ____cacheline_aligned;
--
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