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greybus: kernel_ver: add sg copy operations for kernel < 3.11 

For older kernel, < 3.11, no copy to/from buffer with skip support was
defined. This could break builds for this versions of kernel.
Add them here.

Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Tested-by: Mark Greer <mgreer@animalcreek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
hifive-unleashed-5.1
Rui Miguel Silva 2015-06-24 23:20:27 +01:00 committed by Greg Kroah-Hartman
parent 5656ab99a0
commit 8a01b408a6
1 changed files with 100 additions and 0 deletions
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100
drivers/staging/greybus/kernel_ver.h
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@ -135,4 +135,104 @@ static inline void sysfs_remove_groups(struct kobject *kobj,
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 17, 0)
#define MMC_POWER_UNDEFINED_SUPPORTED
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 11, 0)
#include <linux/scatterlist.h>
static inline bool sg_miter_get_next_page(struct sg_mapping_iter *miter)
{
if (!miter->__remaining) {
struct scatterlist *sg;
unsigned long pgoffset;
if (!__sg_page_iter_next(&miter->piter))
return false;
sg = miter->piter.sg;
pgoffset = miter->piter.sg_pgoffset;
miter->__offset = pgoffset ? 0 : sg->offset;
miter->__remaining = sg->offset + sg->length -
(pgoffset << PAGE_SHIFT) - miter->__offset;
miter->__remaining = min_t(unsigned long, miter->__remaining,
PAGE_SIZE - miter->__offset);
}
return true;
}
static inline bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset)
{
sg_miter_stop(miter);
while (offset) {
off_t consumed;
if (!sg_miter_get_next_page(miter))
return false;
consumed = min_t(off_t, offset, miter->__remaining);
miter->__offset += consumed;
miter->__remaining -= consumed;
offset -= consumed;
}
return true;
}
static inline size_t _sg_copy_buffer(struct scatterlist *sgl,
unsigned int nents, void *buf,
size_t buflen, off_t skip,
bool to_buffer)
{
unsigned int offset = 0;
struct sg_mapping_iter miter;
unsigned long flags;
unsigned int sg_flags = SG_MITER_ATOMIC;
if (to_buffer)
sg_flags |= SG_MITER_FROM_SG;
else
sg_flags |= SG_MITER_TO_SG;
sg_miter_start(&miter, sgl, nents, sg_flags);
if (!sg_miter_skip(&miter, skip))
return false;
local_irq_save(flags);
while (sg_miter_next(&miter) && offset < buflen) {
unsigned int len;
len = min(miter.length, buflen - offset);
if (to_buffer)
memcpy(buf + offset, miter.addr, len);
else
memcpy(miter.addr, buf + offset, len);
offset += len;
}
sg_miter_stop(&miter);
local_irq_restore(flags);
return offset;
}
static inline size_t sg_pcopy_to_buffer(struct scatterlist *sgl,
unsigned int nents, void *buf,
size_t buflen, off_t skip)
{
return _sg_copy_buffer(sgl, nents, buf, buflen, skip, true);
}
static inline size_t sg_pcopy_from_buffer(struct scatterlist *sgl,
unsigned int nents, void *buf,
size_t buflen, off_t skip)
{
return _sg_copy_buffer(sgl, nents, buf, buflen, skip, false);
}
#endif
#endif /* __GREYBUS_KERNEL_VER_H */