From: Jan Höppner Date: Thu, 16 Oct 2025 07:47:18 +0000 (+0200) Subject: s390/tape: Add support for bigger block sizes X-Git-Tag: v6.19-rc1~206^2~35^2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=319d3d66537e615e0729ae734099fe01581bc09d;p=thirdparty%2Flinux.git s390/tape: Add support for bigger block sizes The tape device type 3590/3592 and emulated 3490 VTS can handle a block size of up to 256K bytes. Currently the tape device driver is limited to a block size of 65535 bytes (64K-1). This limitation stems from the maximum of 65535 bytes of data that can be transferred with one Channel-Command Word (CCW). To work around this limitation data chaining is used which uses several CCW to transfer an entire 256K block of data. A single CCW holds a maximum of 65535 bytes of data. Set MAX_BLOCKSIZE to 262144 (= 256K) to allow for data transfers with larger block sizes. The read_block() and write_block() discipline functions calculate the number of CCWs required based on the IDAL buffer array size that was created for a given block size. If there is more than one CCW required for the data transfer, the new helper function tape_ccw_dc_idal() is used to build the data chain accordingly. The Interruption-Repsonse Block (irb) is added to the tape_request struct so that the tapechar_read/write() functions can analyze what data was read or written accordingly. Signed-off-by: Jan Höppner Reviewed-by: Jens Remus Signed-off-by: Heiko Carstens --- diff --git a/drivers/s390/char/tape.h b/drivers/s390/char/tape.h index 6e97b26d4e70a..3953b31b0c559 100644 --- a/drivers/s390/char/tape.h +++ b/drivers/s390/char/tape.h @@ -130,6 +130,7 @@ struct tape_request { int retries; /* retry counter for error recovery. */ int rescnt; /* residual count from devstat. */ struct timer_list timer; /* timer for std_assign_timeout(). */ + struct irb irb; /* device status */ /* Callback for delivering final status. */ void (*callback)(struct tape_request *, void *); @@ -347,6 +348,15 @@ tape_ccw_repeat(struct ccw1 *ccw, __u8 cmd_code, int count) return ccw; } +static inline struct ccw1 * +tape_ccw_dc_idal(struct ccw1 *ccw, __u8 cmd_code, struct idal_buffer *idal) +{ + ccw->cmd_code = cmd_code; + ccw->flags = CCW_FLAG_DC; + idal_buffer_set_cda(idal, ccw); + return ccw + 1; +} + static inline struct ccw1 * tape_ccw_cc_idal(struct ccw1 *ccw, __u8 cmd_code, struct idal_buffer *idal) { diff --git a/drivers/s390/char/tape_char.c b/drivers/s390/char/tape_char.c index bcc49e9eabb8d..96e6c8a5735ed 100644 --- a/drivers/s390/char/tape_char.c +++ b/drivers/s390/char/tape_char.c @@ -100,9 +100,12 @@ tapechar_cleanup_device(struct tape_device *device) static ssize_t tapechar_read(struct file *filp, char __user *data, size_t count, loff_t *ppos) { - struct tape_device *device; struct tape_request *request; + struct ccw1 *ccw, *last_ccw; + struct tape_device *device; + struct idal_buffer **ibs; size_t block_size; + size_t read = 0; int rc; DBF_EVENT(6, "TCHAR:read\n"); @@ -141,12 +144,25 @@ tapechar_read(struct file *filp, char __user *data, size_t count, loff_t *ppos) /* Execute it. */ rc = tape_do_io(device, request); if (rc == 0) { - rc = block_size - request->rescnt; DBF_EVENT(6, "TCHAR:rbytes: %x\n", rc); - /* Copy data from idal buffer to user space. */ - if (idal_buffer_to_user(*device->char_data.ibs, - data, rc) != 0) - rc = -EFAULT; + /* Channel Program Address (cpa) points to last CCW + 8 */ + last_ccw = dma32_to_virt(request->irb.scsw.cmd.cpa); + ccw = request->cpaddr; + ibs = device->char_data.ibs; + while (++ccw < last_ccw) { + /* Copy data from idal buffer to user space. */ + if (idal_buffer_to_user(*ibs++, data, ccw->count) != 0) { + rc = -EFAULT; + break; + } + read += ccw->count; + data += ccw->count; + } + if (&last_ccw[-1] == &request->cpaddr[1] && + request->rescnt == last_ccw[-1].count) + rc = 0; + else + rc = read - request->rescnt; } tape_free_request(request); return rc; @@ -158,10 +174,12 @@ tapechar_read(struct file *filp, char __user *data, size_t count, loff_t *ppos) static ssize_t tapechar_write(struct file *filp, const char __user *data, size_t count, loff_t *ppos) { - struct tape_device *device; struct tape_request *request; + struct ccw1 *ccw, *last_ccw; + struct tape_device *device; + struct idal_buffer **ibs; + size_t written = 0; size_t block_size; - size_t written; int nblocks; int i, rc; @@ -185,31 +203,41 @@ tapechar_write(struct file *filp, const char __user *data, size_t count, loff_t if (rc) return rc; - DBF_EVENT(6,"TCHAR:nbytes: %lx\n", block_size); + DBF_EVENT(6, "TCHAR:nbytes: %lx\n", block_size); DBF_EVENT(6, "TCHAR:nblocks: %x\n", nblocks); /* Let the discipline build the ccw chain. */ request = device->discipline->write_block(device); if (IS_ERR(request)) return PTR_ERR(request); - rc = 0; - written = 0; + for (i = 0; i < nblocks; i++) { - /* Copy data from user space to idal buffer. */ - if (idal_buffer_from_user(*device->char_data.ibs, - data, block_size)) { - rc = -EFAULT; - break; + size_t wbytes = 0; /* Used to trace written data in dbf */ + + ibs = device->char_data.ibs; + while (ibs && *ibs) { + if (idal_buffer_from_user(*ibs, data, (*ibs)->size)) { + rc = -EFAULT; + goto out; + } + data += (*ibs)->size; + ibs++; } rc = tape_do_io(device, request); if (rc) - break; - DBF_EVENT(6, "TCHAR:wbytes: %lx\n", - block_size - request->rescnt); - written += block_size - request->rescnt; + goto out; + + /* Channel Program Address (cpa) points to last CCW + 8 */ + last_ccw = dma32_to_virt(request->irb.scsw.cmd.cpa); + ccw = request->cpaddr; + while (++ccw < last_ccw) + wbytes += ccw->count; + DBF_EVENT(6, "TCHAR:wbytes: %lx\n", wbytes - request->rescnt); + written += wbytes - request->rescnt; if (request->rescnt != 0) break; - data += block_size; } + +out: tape_free_request(request); if (rc == -ENOSPC) { /* diff --git a/drivers/s390/char/tape_core.c b/drivers/s390/char/tape_core.c index 304c6eae139c9..ab1a2dc7d711a 100644 --- a/drivers/s390/char/tape_core.c +++ b/drivers/s390/char/tape_core.c @@ -1129,9 +1129,10 @@ __tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb) } /* May be an unsolicited irq */ - if(request != NULL) + if (request != NULL) { request->rescnt = irb->scsw.cmd.count; - else if ((irb->scsw.cmd.dstat == 0x85 || irb->scsw.cmd.dstat == 0x80) && + memcpy(&request->irb, irb, sizeof(*irb)); + } else if ((irb->scsw.cmd.dstat == 0x85 || irb->scsw.cmd.dstat == 0x80) && !list_empty(&device->req_queue)) { /* Not Ready to Ready after long busy ? */ struct tape_request *req; diff --git a/drivers/s390/char/tape_std.c b/drivers/s390/char/tape_std.c index 5f3646f78bfac..4e1c52313fbcd 100644 --- a/drivers/s390/char/tape_std.c +++ b/drivers/s390/char/tape_std.c @@ -630,16 +630,23 @@ struct tape_request * tape_std_read_block(struct tape_device *device) { struct tape_request *request; + struct idal_buffer **ibs; + struct ccw1 *ccw; + size_t count; - request = tape_alloc_request(2, 0); + ibs = device->char_data.ibs; + count = idal_buffer_array_size(ibs); + request = tape_alloc_request(count + 1 /* MODE_SET_DB */, 0); if (IS_ERR(request)) { DBF_EXCEPTION(6, "xrbl fail"); return request; } request->op = TO_RFO; - tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte); - tape_ccw_end_idal(request->cpaddr + 1, READ_FORWARD, - *device->char_data.ibs); + ccw = tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte); + while (count-- > 1) + ccw = tape_ccw_dc_idal(ccw, READ_FORWARD, *ibs++); + tape_ccw_end_idal(ccw, READ_FORWARD, *ibs); + DBF_EVENT(6, "xrbl ccwg\n"); return request; } @@ -651,16 +658,23 @@ struct tape_request * tape_std_write_block(struct tape_device *device) { struct tape_request *request; + struct idal_buffer **ibs; + struct ccw1 *ccw; + size_t count; - request = tape_alloc_request(2, 0); + count = idal_buffer_array_size(device->char_data.ibs); + request = tape_alloc_request(count + 1 /* MODE_SET_DB */, 0); if (IS_ERR(request)) { DBF_EXCEPTION(6, "xwbl fail\n"); return request; } request->op = TO_WRI; - tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte); - tape_ccw_end_idal(request->cpaddr + 1, WRITE_CMD, - *device->char_data.ibs); + ccw = tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte); + ibs = device->char_data.ibs; + while (count-- > 1) + ccw = tape_ccw_dc_idal(ccw, WRITE_CMD, *ibs++); + tape_ccw_end_idal(ccw, WRITE_CMD, *ibs); + DBF_EVENT(6, "xwbl ccwg\n"); return request; } diff --git a/drivers/s390/char/tape_std.h b/drivers/s390/char/tape_std.h index eefeb5484214b..2cf9f725b3b3f 100644 --- a/drivers/s390/char/tape_std.h +++ b/drivers/s390/char/tape_std.h @@ -14,10 +14,9 @@ #include /* - * Biggest block size to handle. Currently 64K because we only build - * channel programs without data chaining. + * Biggest block size of 256K to handle. */ -#define MAX_BLOCKSIZE 65535 +#define MAX_BLOCKSIZE 262144 /* * The CCW commands for the Tape type of command.