Re: 2.6.22-rc3-mm1

Cornelia Huck
2007-05-31T12:09:32Z

On Wed, 30 May 2007 23:58:23 -0700,
Andrew Morton <akpm@linux-foundation.org> wrote:

>
> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.22-rc3/2.6.22-rc3-mm1/

With

> +dma-mapping-prevent-dma-dependent-code-from-linking-on.patch

scsi fails to build on !HAS_DMA architectures:

drivers/built-in.o(.text+0x20af6): In function `scsi_dma_map':
: undefined reference to `dma_map_sg'
drivers/built-in.o(.text+0x20b5c): In function `scsi_dma_unmap':
: undefined reference to `dma_unmap_sg'

I split those functions out into a new file. Builds on s390 and i386.

scsi: Don't build scsi_dma_{map,unmap} for !HAS_DMA

Move scsi_dma_{map,unmap} into scsi_lib_dma.c which is only build
if HAS_DMA is set.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

---
drivers/scsi/Kconfig | 5 ++++
drivers/scsi/Makefile | 6 ++---
drivers/scsi/scsi_lib.c | 38 ---------------------------------
drivers/scsi/scsi_lib_dma.c | 50 ++++++++++++++++++++++++++++++++++++++++++++
include/scsi/scsi_cmnd.h | 2 +
5 files changed, 60 insertions(+), 41 deletions(-)

--- linux-2.6.orig/drivers/scsi/Kconfig
+++ linux-2.6/drivers/scsi/Kconfig
@@ -10,6 +10,7 @@ config RAID_ATTRS
config SCSI
tristate "SCSI device support"
depends on BLOCK
+ select SCSI_DMA if HAS_DMA
---help---
If you want to use a SCSI hard disk, SCSI tape drive, SCSI CD-ROM or
any other SCSI device under Linux, say Y and make sure that you know
@@ -29,6 +30,10 @@ config SCSI
However, do not compile this as a module if your root file system
(the one containing the directory /) is located on a SCSI device.

+config SCSI_DMA
+ bool
+ default n
+
config SCSI_TGT
tristate "SCSI target support"
depends on SCSI && EXPERIMENTAL
--- linux-2.6.orig/drivers/scsi/Makefile
+++ linux-2.6/drivers/scsi/Makefile
@@ -145,9 +145,9 @@ obj-$(CONFIG_SCSI_DEBUG) += scsi_debug.o
obj-$(CONFIG_SCSI_WAIT_SCAN) += scsi_wait_scan.o

scsi_mod-y += scsi.o hosts.o scsi_ioctl.o constants.o \
- scsicam.o scsi_error.o scsi_lib.o \
- scsi_scan.o scsi_sysfs.o \
- scsi_devinfo.o
+ scsicam.o scsi_error.o scsi_lib.o
+scsi_mod-$(CONFIG_SCSI_DMA) += scsi_lib_dma.o
+scsi_mod-y += scsi_scan.o scsi_sysfs.o scsi_devinfo.o
scsi_mod-$(CONFIG_SCSI_NETLINK) += scsi_netlink.o
scsi_mod-$(CONFIG_SYSCTL) += scsi_sysctl.o
scsi_mod-$(CONFIG_SCSI_PROC_FS) += scsi_proc.o
--- linux-2.6.orig/drivers/scsi/scsi_lib.c
+++ linux-2.6/drivers/scsi/scsi_lib.c
@@ -2290,41 +2290,3 @@ void scsi_kunmap_atomic_sg(void *virt)
kunmap_atomic(virt, KM_BIO_SRC_IRQ);
}
EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
-
-/**
- * scsi_dma_map - perform DMA mapping against command's sg lists
- * @cmd: scsi command
- *
- * Returns the number of sg lists actually used, zero if the sg lists
- * is NULL, or -ENOMEM if the mapping failed.
- */
-int scsi_dma_map(struct scsi_cmnd *cmd)
-{
- int nseg = 0;
-
- if (scsi_sg_count(cmd)) {
- struct device *dev = cmd->device->host->shost_gendev.parent;
-
- nseg = dma_map_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
- cmd->sc_data_direction);
- if (unlikely(!nseg))
- return -ENOMEM;
- }
- return nseg;
-}
-EXPORT_SYMBOL(scsi_dma_map);
-
-/**
- * scsi_dma_unmap - unmap command's sg lists mapped by scsi_dma_map
- * @cmd: scsi command
- */
-void scsi_dma_unmap(struct scsi_cmnd *cmd)
-{
- if (scsi_sg_count(cmd)) {
- struct device *dev = cmd->device->host->shost_gendev.parent;
-
- dma_unmap_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
- cmd->sc_data_direction);
- }
-}
-EXPORT_SYMBOL(scsi_dma_unmap);
--- linux-2.6.orig/include/scsi/scsi_cmnd.h
+++ linux-2.6/include/scsi/scsi_cmnd.h
@@ -135,8 +135,10 @@ extern void scsi_kunmap_atomic_sg(void *
extern struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *, gfp_t);
extern void scsi_free_sgtable(struct scatterlist *, int);

+#ifdef CONFIG_SCSI_DMA
extern int scsi_dma_map(struct scsi_cmnd *cmd);
extern void scsi_dma_unmap(struct scsi_cmnd *cmd);
+#endif

#define scsi_sg_count(cmd) ((cmd)->use_sg)
#define scsi_sglist(cmd) ((struct scatterlist *)(cmd)->request_buffer)
--- /dev/null
+++ linux-2.6/drivers/scsi/scsi_lib_dma.c
@@ -0,0 +1,50 @@
+/*
+ * SCSI library functions depending on DMA
+ */
+
+#include <linux/blkdev.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_host.h>
+
+/**
+ * scsi_dma_map - perform DMA mapping against command's sg lists
+ * @cmd: scsi command
+ *
+ * Returns the number of sg lists actually used, zero if the sg lists
+ * is NULL, or -ENOMEM if the mapping failed.
+ */
+int scsi_dma_map(struct scsi_cmnd *cmd)
+{
+ int nseg = 0;
+
+ if (scsi_sg_count(cmd)) {
+ struct device *dev = cmd->device->host->shost_gendev.parent;
+
+ nseg = dma_map_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
+ cmd->sc_data_direction);
+ if (unlikely(!nseg))
+ return -ENOMEM;
+ }
+ return nseg;
+}
+EXPORT_SYMBOL(scsi_dma_map);
+
+/**
+ * scsi_dma_unmap - unmap command's sg lists mapped by scsi_dma_map
+ * @cmd: scsi command
+ */
+void scsi_dma_unmap(struct scsi_cmnd *cmd)
+{
+ if (scsi_sg_count(cmd)) {
+ struct device *dev = cmd->device->host->shost_gendev.parent;
+
+ dma_unmap_sg(dev, scsi_sglist(cmd), scsi_sg_count(cmd),
+ cmd->sc_data_direction);
+ }
+}
+EXPORT_SYMBOL(scsi_dma_unmap);