[PATCH v2] usb: gadget: storage: add support for media larger than 2T

Nikita Yushchenko
2021-09-14T20:09:43Z

This adds support for READ_CAPACITY(16), READ(16) and WRITE(16)
commands, and fixes READ_CAPACITY command to return 0xffffffff if
media size does not fit in 32 bits.

This makes f_mass_storage to export a 16T disk array correctly.

Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
---
drivers/usb/gadget/function/f_mass_storage.c | 87 ++++++++++++++++++--
1 file changed, 80 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c
index 7c96c4665178..96de401f1282 100644
--- a/drivers/usb/gadget/function/f_mass_storage.c
+++ b/drivers/usb/gadget/function/f_mass_storage.c
@@ -619,7 +619,7 @@ static int sleep_thread(struct fsg_common *common, bool can_freeze,
static int do_read(struct fsg_common *common)
{
struct fsg_lun *curlun = common->curlun;
- u32 lba;
+ u64 lba;
struct fsg_buffhd *bh;
int rc;
u32 amount_left;
@@ -634,7 +634,10 @@ static int do_read(struct fsg_common *common)
if (common->cmnd[0] == READ_6)
lba = get_unaligned_be24(&common->cmnd[1]);
else {
- lba = get_unaligned_be32(&common->cmnd[2]);
+ if (common->cmnd[0] == READ_16)
+ lba = get_unaligned_be64(&common->cmnd[2]);
+ else /* READ_10 or READ_12 */
+ lba = get_unaligned_be32(&common->cmnd[2]);

/*
* We allow DPO (Disable Page Out = don't save data in the
@@ -747,7 +750,7 @@ static int do_read(struct fsg_common *common)
static int do_write(struct fsg_common *common)
{
struct fsg_lun *curlun = common->curlun;
- u32 lba;
+ u64 lba;
struct fsg_buffhd *bh;
int get_some_more;
u32 amount_left_to_req, amount_left_to_write;
@@ -771,7 +774,10 @@ static int do_write(struct fsg_common *common)
if (common->cmnd[0] == WRITE_6)
lba = get_unaligned_be24(&common->cmnd[1]);
else {
- lba = get_unaligned_be32(&common->cmnd[2]);
+ if (common->cmnd[0] == WRITE_16)
+ lba = get_unaligned_be64(&common->cmnd[2]);
+ else /* WRITE_10 or WRITE_12 */
+ lba = get_unaligned_be32(&common->cmnd[2]);

/*
* We allow DPO (Disable Page Out = don't save data in the
@@ -1146,6 +1152,7 @@ static int do_read_capacity(struct fsg_common *common, struct fsg_buffhd *bh)
u32 lba = get_unaligned_be32(&common->cmnd[2]);
int pmi = common->cmnd[8];
u8 *buf = (u8 *)bh->buf;
+ u32 max_lba;

/* Check the PMI and LBA fields */
if (pmi > 1 || (pmi == 0 && lba != 0)) {
@@ -1153,12 +1160,37 @@ static int do_read_capacity(struct fsg_common *common, struct fsg_buffhd *bh)
return -EINVAL;
}

- put_unaligned_be32(curlun->num_sectors - 1, &buf[0]);
- /* Max logical block */
- put_unaligned_be32(curlun->blksize, &buf[4]);/* Block length */
+ if (curlun->num_sectors < 0x100000000ULL)
+ max_lba = curlun->num_sectors - 1;
+ else
+ max_lba = 0xffffffff;
+ put_unaligned_be32(max_lba, &buf[0]); /* Max logical block */
+ put_unaligned_be32(curlun->blksize, &buf[4]); /* Block length */
return 8;
}

+static int do_read_capacity_16(struct fsg_common *common, struct fsg_buffhd *bh)
+{
+ struct fsg_lun *curlun = common->curlun;
+ u64 lba = get_unaligned_be64(&common->cmnd[2]);
+ int pmi = common->cmnd[14];
+ u8 *buf = (u8 *)bh->buf;
+
+ /* Check the PMI and LBA fields */
+ if (pmi > 1 || (pmi == 0 && lba != 0)) {
+ curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+ return -EINVAL;
+ }
+
+ put_unaligned_be64(curlun->num_sectors - 1, &buf[0]);
+ /* Max logical block */
+ put_unaligned_be32(curlun->blksize, &buf[8]); /* Block length */
+
+ /* It is safe to keep other fields zeroed */
+ memset(&buf[12], 0, 32 - 12);
+ return 32;
+}
+
static int do_read_header(struct fsg_common *common, struct fsg_buffhd *bh)
{
struct fsg_lun *curlun = common->curlun;
@@ -1905,6 +1937,17 @@ static int do_scsi_command(struct fsg_common *common)
reply = do_read(common);
break;

+ case READ_16:
+ common->data_size_from_cmnd =
+ get_unaligned_be32(&common->cmnd[10]);
+ reply = check_command_size_in_blocks(common, 16,
+ DATA_DIR_TO_HOST,
+ (1<<1) | (0xff<<2) | (0xf<<10), 1,
+ "READ(16)");
+ if (reply == 0)
+ reply = do_read(common);
+ break;
+
case READ_CAPACITY:
common->data_size_from_cmnd = 8;
reply = check_command(common, 10, DATA_DIR_TO_HOST,
@@ -1957,6 +2000,25 @@ static int do_scsi_command(struct fsg_common *common)
reply = do_request_sense(common, bh);
break;

+ case SERVICE_ACTION_IN_16:
+ switch (common->cmnd[1] & 0x1f) {
+
+ case SAI_READ_CAPACITY_16:
+ common->data_size_from_cmnd =
+ get_unaligned_be32(&common->cmnd[10]);
+ reply = check_command(common, 16, DATA_DIR_TO_HOST,
+ (1<<1) | (0xff<<2) | (0xf<<10) |
+ (1<<14), 1,
+ "READ CAPACITY(16)");
+ if (reply == 0)
+ reply = do_read_capacity_16(common, bh);
+ break;
+
+ default:
+ goto unknown_cmnd;
+ }
+ break;
+
case START_STOP:
common->data_size_from_cmnd = 0;
reply = check_command(common, 6, DATA_DIR_NONE,
@@ -2028,6 +2090,17 @@ static int do_scsi_command(struct fsg_common *common)
reply = do_write(common);
break;

+ case WRITE_16:
+ common->data_size_from_cmnd =
+ get_unaligned_be32(&common->cmnd[10]);
+ reply = check_command_size_in_blocks(common, 16,
+ DATA_DIR_FROM_HOST,
+ (1<<1) | (0xff<<2) | (0xf<<10), 1,
+ "WRITE(16)");
+ if (reply == 0)
+ reply = do_write(common);
+ break;
+
/*
* Some mandatory commands that we recognize but don't implement.
* They don't mean much in this setting. It's left as an exercise
--
2.20.1