From: Ira Weiny <ira.weiny@xxxxxxxxx> kmap() is being deprecated and will break uses of device dax after PKS protection is introduced.[1] The use of kmap() in siw_tx_hdt() is all thread local therefore kmap_local_page() is a sufficient replacement and will work with pgmap protected pages when those are implemented. siw_tx_hdt() tracks pages used in a page_array. It uses that array to unmap pages which were mapped on function exit. Not all entries in the array are mapped and this is tracked in kmap_mask. kunmap_local() takes a mapped address rather than a page. Alter siw_unmap_pages() to take the iov array to reuse the iov_base address of each mapping. Use PAGE_MASK to get the proper address for kunmap_local(). kmap_local_page() mappings are tracked in a stack and must be unmapped in the opposite order they were mapped in. Because segments are mapped into the page array in increasing index order, modify siw_unmap_pages() to unmap pages in decreasing order. Use kmap_local_page() instead of kmap() to map pages in the page_array. [1] https://lore.kernel.org/lkml/20201009195033.3208459-59-ira.weiny@xxxxxxxxx/ Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> --- Changes for V2: From Bernard Reuse iov[].iov_base rather than declaring another array of pointers and preserve the use of kmap_mask to know which iov's were kmapped. --- drivers/infiniband/sw/siw/siw_qp_tx.c | 32 +++++++++++++++++---------- 1 file changed, 20 insertions(+), 12 deletions(-) diff --git a/drivers/infiniband/sw/siw/siw_qp_tx.c b/drivers/infiniband/sw/siw/siw_qp_tx.c index db68a10d12cd..fd3b9e6a67d7 100644 --- a/drivers/infiniband/sw/siw/siw_qp_tx.c +++ b/drivers/infiniband/sw/siw/siw_qp_tx.c @@ -396,13 +396,20 @@ static int siw_0copy_tx(struct socket *s, struct page **page, #define MAX_TRAILER (MPA_CRC_SIZE + 4) -static void siw_unmap_pages(struct page **pp, unsigned long kmap_mask) +static void siw_unmap_pages(struct kvec *iov, unsigned long kmap_mask, int len) { - while (kmap_mask) { - if (kmap_mask & BIT(0)) - kunmap(*pp); - pp++; - kmap_mask >>= 1; + int i; + + /* + * Work backwards through the array to honor the kmap_local_page() + * ordering requirements. + */ + for (i = (len-1); i >= 0; i--) { + if (kmap_mask & BIT(i)) { + unsigned long addr = (unsigned long)iov[i].iov_base; + + kunmap_local((void *)(addr & PAGE_MASK)); + } } } @@ -498,7 +505,7 @@ static int siw_tx_hdt(struct siw_iwarp_tx *c_tx, struct socket *s) p = siw_get_upage(mem->umem, sge->laddr + sge_off); if (unlikely(!p)) { - siw_unmap_pages(page_array, kmap_mask); + siw_unmap_pages(iov, kmap_mask, MAX_ARRAY); wqe->processed -= c_tx->bytes_unsent; rv = -EFAULT; goto done_crc; @@ -506,11 +513,12 @@ static int siw_tx_hdt(struct siw_iwarp_tx *c_tx, struct socket *s) page_array[seg] = p; if (!c_tx->use_sendpage) { - iov[seg].iov_base = kmap(p) + fp_off; - iov[seg].iov_len = plen; + void *kaddr = kmap_local_page(page_array[seg]); /* Remember for later kunmap() */ kmap_mask |= BIT(seg); + iov[seg].iov_base = kaddr + fp_off; + iov[seg].iov_len = plen; if (do_crc) crypto_shash_update( @@ -518,7 +526,7 @@ static int siw_tx_hdt(struct siw_iwarp_tx *c_tx, struct socket *s) iov[seg].iov_base, plen); } else if (do_crc) { - kaddr = kmap_local_page(p); + kaddr = kmap_local_page(page_array[seg]); crypto_shash_update(c_tx->mpa_crc_hd, kaddr + fp_off, plen); @@ -542,7 +550,7 @@ static int siw_tx_hdt(struct siw_iwarp_tx *c_tx, struct socket *s) if (++seg > (int)MAX_ARRAY) { siw_dbg_qp(tx_qp(c_tx), "to many fragments\n"); - siw_unmap_pages(page_array, kmap_mask); + siw_unmap_pages(iov, kmap_mask, MAX_ARRAY); wqe->processed -= c_tx->bytes_unsent; rv = -EMSGSIZE; goto done_crc; @@ -593,7 +601,7 @@ static int siw_tx_hdt(struct siw_iwarp_tx *c_tx, struct socket *s) } else { rv = kernel_sendmsg(s, &msg, iov, seg + 1, hdr_len + data_len + trl_len); - siw_unmap_pages(page_array, kmap_mask); + siw_unmap_pages(iov, kmap_mask, MAX_ARRAY); } if (rv < (int)hdr_len) { /* Not even complete hdr pushed or negative rv */ -- 2.28.0.rc0.12.gb6a658bd00c9
