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pmem: reduce kmap_atomic sections to the memcpys only 

pmem_do_bvec used to kmap_atomic at the begin, and only unmap at the
end. Things like nvdimm_clear_poison may want to do nvdimm subsystem
bookkeeping operations that may involve taking locks or doing memory
allocations, and we can't do that from the atomic context. Reduce the
atomic context to just what needs it - the memcpy to/from pmem.

Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
hifive-unleashed-5.1
Vishal Verma 2016-09-30 17:19:30 -06:00 committed by Dan Williams
parent 9ffd6350a1
commit bd697a80c3
1 changed files with 23 additions and 5 deletions
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28
drivers/nvdimm/pmem.c
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@ -66,13 +66,32 @@ static void pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
invalidate_pmem(pmem->virt_addr + offset, len);
}
static void write_pmem(void *pmem_addr, struct page *page,
unsigned int off, unsigned int len)
{
void *mem = kmap_atomic(page);
memcpy_to_pmem(pmem_addr, mem + off, len);
kunmap_atomic(mem);
}
static int read_pmem(struct page *page, unsigned int off,
void *pmem_addr, unsigned int len)
{
int rc;
void *mem = kmap_atomic(page);
rc = memcpy_from_pmem(mem + off, pmem_addr, len);
kunmap_atomic(mem);
return rc;
}
static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
unsigned int len, unsigned int off, bool is_write,
sector_t sector)
{
int rc = 0;
bool bad_pmem = false;
void *mem = kmap_atomic(page);
phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
void *pmem_addr = pmem->virt_addr + pmem_off;
@ -83,7 +102,7 @@ static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
if (unlikely(bad_pmem))
rc = -EIO;
else {
rc = memcpy_from_pmem(mem + off, pmem_addr, len);
rc = read_pmem(page, off, pmem_addr, len);
flush_dcache_page(page);
}
} else {
@ -102,14 +121,13 @@ static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
* after clear poison.
*/
flush_dcache_page(page);
memcpy_to_pmem(pmem_addr, mem + off, len);
write_pmem(pmem_addr, page, off, len);
if (unlikely(bad_pmem)) {
pmem_clear_poison(pmem, pmem_off, len);
memcpy_to_pmem(pmem_addr, mem + off, len);
write_pmem(pmem_addr, page, off, len);
}
}
kunmap_atomic(mem);
return rc;
}