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From:   Nikita Yushchenko <nikita.yoush@cogentembedded.com>
To:     Felipe Balbi <balbi@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Petr Nechaev <petr.nechaev@cogentembedded.com>,
        Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Subject: [PATCH] usb: gadget: storage: add support for media larger than 2T
Date:   Tue, 14 Sep 2021 08:27:28 +0300
Message-Id: <20210914052728.23369-1-nikita.yoush@cogentembedded.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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 | 70 ++++++++++++++++++--
 1 file changed, 63 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..b79737c19750 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
+			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
+			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		mlb;
 
 	/* Check the PMI and LBA fields */
 	if (pmi > 1 || (pmi == 0 && lba != 0)) {
@@ -1153,12 +1160,28 @@ 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)
+		mlb = curlun->num_sectors - 1;
+	else
+		mlb = 0xffffffff;
+	put_unaligned_be32(mlb, &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;
+	u8		*buf = (u8 *)bh->buf;
+
+	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 +1928,17 @@ 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,
@@ -1914,6 +1948,17 @@ static int do_scsi_command(struct fsg_common *common)
 			reply = do_read_capacity(common, bh);
 		break;
 
+	case SERVICE_ACTION_IN_16:
+		if ((common->cmnd[1] & 0x1f) != SAI_READ_CAPACITY_16)
+			goto unknown_cmnd;
+		common->data_size_from_cmnd = 32;
+		reply = check_command(common, 14, DATA_DIR_TO_HOST,
+				      (1<<1) | (1<<13), 1,
+				      "READ CAPACITY(16)");
+		if (reply == 0)
+			reply = do_read_capacity_16(common, bh);
+		break;
+
 	case READ_HEADER:
 		if (!common->curlun || !common->curlun->cdrom)
 			goto unknown_cmnd;
@@ -2028,6 +2073,17 @@ 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