Commit 9d649d59 authored by Ira Weiny's avatar Ira Weiny Committed by Jason Gunthorpe
Browse files

RDMA/siw: Convert siw_tx_hdt() to kmap_local_page() 

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@intel.com/

Link: https://lore.kernel.org/r/20210624174814.2822896-1-ira.weiny@intel.com


Signed-off-by: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarBernard Metzler <bmt@zurich.ibm.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 1ec50dd1

drivers/infiniband/sw/siw/siw_qp_tx.c

+19 −11
Original line number Diff line number Diff line
@@ -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, seg);

					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(p);



					/* 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(
@@ -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, seg-1);

				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, seg);

	}

	if (rv < (int)hdr_len) {

		/* Not even complete hdr pushed or negative rv */