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mem: fix alignment of requested virtual areas

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The original code did not align any addresses that were requested as
page-aligned, but were different because addr_is_hint was set.

Below fix by Dariusz has introduced an issue where all unaligned addresses
were left as unaligned.

This patch is a partial revert of
commit 7fa7216ed4 ("mem: fix alignment of requested virtual areas")

and implements a proper fix for this issue, by asking for alignment in all
but the following two cases:

1) page size is equal to system page size, or
2) we got an aligned requested address, and will not accept a different one

This ensures that alignment is performed in all cases, except for those we
can guarantee that the address will not need alignment.

Fixes: b7cc54187e ("mem: move virtual area function in common directory")
Fixes: 7fa7216ed4 ("mem: fix alignment of requested virtual areas")
Cc: stable@dpdk.org

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Tested-by: Lei Yao <lei.a.yao@intel.com>
Acked-by: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
This commit is contained in:
Anatoly Burakov 2018-07-16 15:57:19 +01:00 committed by Thomas Monjalon
parent b7167593e0
commit d5dd22c9f6
1 changed files with 9 additions and 6 deletions
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15
lib/librte_eal/common/eal_common_memory.c
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@ -66,14 +66,17 @@ eal_get_virtual_area(void *requested_addr, size_t *size,
addr_is_hint = true;
}
/* if requested address is not aligned by page size, or if requested
* address is NULL, add page size to requested length as we may get an
* address that's aligned by system page size, which can be smaller than
* our requested page size. additionally, we shouldn't try to align if
* system page size is the same as requested page size.
/* we don't need alignment of resulting pointer in the following cases:
*
* 1. page size is equal to system size
* 2. we have a requested address, and it is page-aligned, and we will
* be discarding the address if we get a different one.
*
* for all other cases, alignment is potentially necessary.
*/
no_align = (requested_addr != NULL &&
((uintptr_t)requested_addr & (page_sz - 1))) ||
requested_addr == RTE_PTR_ALIGN(requested_addr, page_sz) &&
!addr_is_hint) ||
page_sz == system_page_sz;
do {