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Message-ID: <20180918063853.198332-5-namit@vmware.com>
Date: Mon, 17 Sep 2018 23:38:38 -0700
From: Nadav Amit <namit@...are.com>
To: Arnd Bergmann <arnd@...db.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
CC: <linux-kernel@...r.kernel.org>, Nadav Amit <nadav.amit@...il.com>
Subject: [PATCH 04/19] vmw_balloon: simplifying batch access
From: Nadav Amit <nadav.amit@...il.com>
The use of accessors for batch entries complicates the code and makes it
less readable. Remove it an instead use bit-fields.
Reviewed-by: Xavier Deguillard <xdeguillard@...are.com>
Signed-off-by: Nadav Amit <nadav.amit@...il.com>
---
drivers/misc/vmw_balloon.c | 81 ++++++++++++++------------------------
1 file changed, 30 insertions(+), 51 deletions(-)
diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 5e5f61f207f4..7af70fc988b9 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -121,24 +121,6 @@ enum vmwballoon_capabilities {
#define VMW_BALLOON_SUCCESS_WITH_CAPABILITIES (0x03000000)
-/* Batch page description */
-
-/*
- * Layout of a page in the batch page:
- *
- * +-------------+----------+--------+
- * | | | |
- * | Page number | Reserved | Status |
- * | | | |
- * +-------------+----------+--------+
- * 64 PAGE_SHIFT 6 0
- *
- * The reserved field should be set to 0.
- */
-#define VMW_BALLOON_BATCH_MAX_PAGES (PAGE_SIZE / sizeof(u64))
-#define VMW_BALLOON_BATCH_STATUS_MASK ((1UL << 5) - 1)
-#define VMW_BALLOON_BATCH_PAGE_MASK (~((1UL << PAGE_SHIFT) - 1))
-
#define VMW_BALLOON_CMD_WITH_TARGET_MASK \
((1UL << VMW_BALLOON_CMD_GET_TARGET) | \
(1UL << VMW_BALLOON_CMD_LOCK) | \
@@ -161,27 +143,6 @@ static const char * const vmballoon_cmd_names[] = {
[VMW_BALLOON_CMD_VMCI_DOORBELL_SET] = "doorbellSet"
};
-struct vmballoon_batch_page {
- u64 pages[VMW_BALLOON_BATCH_MAX_PAGES];
-};
-
-static u64 vmballoon_batch_get_pa(struct vmballoon_batch_page *batch, int idx)
-{
- return batch->pages[idx] & VMW_BALLOON_BATCH_PAGE_MASK;
-}
-
-static int vmballoon_batch_get_status(struct vmballoon_batch_page *batch,
- int idx)
-{
- return (int)(batch->pages[idx] & VMW_BALLOON_BATCH_STATUS_MASK);
-}
-
-static void vmballoon_batch_set_pa(struct vmballoon_batch_page *batch, int idx,
- u64 pa)
-{
- batch->pages[idx] = pa;
-}
-
#ifdef CONFIG_DEBUG_FS
struct vmballoon_stats {
unsigned int timer;
@@ -225,6 +186,19 @@ struct vmballoon_page_size {
unsigned int n_refused_pages;
};
+/**
+ * struct vmballoon_batch_entry - a batch entry for lock or unlock.
+ *
+ * @status: the status of the operation, which is written by the hypervisor.
+ * @reserved: reserved for future use. Must be set to zero.
+ * @pfn: the physical frame number of the page to be locked or unlocked.
+ */
+struct vmballoon_batch_entry {
+ u64 status : 5;
+ u64 reserved : PAGE_SHIFT - 5;
+ u64 pfn : 52;
+} __packed;
+
struct vmballoon {
struct vmballoon_page_size page_sizes[VMW_BALLOON_NUM_PAGE_SIZES];
@@ -240,7 +214,14 @@ struct vmballoon {
unsigned long capabilities;
- struct vmballoon_batch_page *batch_page;
+ /**
+ * @batch_page: pointer to communication batch page.
+ *
+ * When batching is used, batch_page points to a page, which holds up to
+ * %VMW_BALLOON_BATCH_MAX_PAGES entries for locking or unlocking.
+ */
+ struct vmballoon_batch_entry *batch_page;
+
unsigned int batch_max_pages;
struct page *page;
@@ -568,8 +549,7 @@ static int vmballoon_lock_batched_page(struct vmballoon *b,
if (locked > 0) {
for (i = 0; i < num_pages; i++) {
- u64 pa = vmballoon_batch_get_pa(b->batch_page, i);
- struct page *p = pfn_to_page(pa >> PAGE_SHIFT);
+ struct page *p = pfn_to_page(b->batch_page[i].pfn);
vmballoon_free_page(p, is_2m_pages);
}
@@ -578,12 +558,11 @@ static int vmballoon_lock_batched_page(struct vmballoon *b,
}
for (i = 0; i < num_pages; i++) {
- u64 pa = vmballoon_batch_get_pa(b->batch_page, i);
- struct page *p = pfn_to_page(pa >> PAGE_SHIFT);
+ struct page *p = pfn_to_page(b->batch_page[i].pfn);
struct vmballoon_page_size *page_size =
&b->page_sizes[is_2m_pages];
- locked = vmballoon_batch_get_status(b->batch_page, i);
+ locked = b->batch_page[i].status;
switch (locked) {
case VMW_BALLOON_SUCCESS:
@@ -656,12 +635,11 @@ static int vmballoon_unlock_batched_page(struct vmballoon *b,
ret = -EIO;
for (i = 0; i < num_pages; i++) {
- u64 pa = vmballoon_batch_get_pa(b->batch_page, i);
- struct page *p = pfn_to_page(pa >> PAGE_SHIFT);
+ struct page *p = pfn_to_page(b->batch_page[i].pfn);
struct vmballoon_page_size *page_size =
&b->page_sizes[is_2m_pages];
- locked = vmballoon_batch_get_status(b->batch_page, i);
+ locked = b->batch_page[i].status;
if (!hv_success || locked != VMW_BALLOON_SUCCESS) {
/*
* That page wasn't successfully unlocked by the
@@ -710,8 +688,8 @@ static void vmballoon_add_page(struct vmballoon *b, int idx, struct page *p)
static void vmballoon_add_batched_page(struct vmballoon *b, int idx,
struct page *p)
{
- vmballoon_batch_set_pa(b->batch_page, idx,
- (u64)page_to_pfn(p) << PAGE_SHIFT);
+ b->batch_page[idx] = (struct vmballoon_batch_entry)
+ { .pfn = page_to_pfn(p) };
}
/*
@@ -967,7 +945,8 @@ static void vmballoon_reset(struct vmballoon *b)
if ((b->capabilities & VMW_BALLOON_BATCHED_CMDS) != 0) {
b->ops = &vmballoon_batched_ops;
- b->batch_max_pages = VMW_BALLOON_BATCH_MAX_PAGES;
+ b->batch_max_pages = PAGE_SIZE / sizeof(struct
+ vmballoon_batch_entry);
if (!vmballoon_init_batching(b)) {
/*
* We failed to initialize batching, inform the monitor
--
2.17.1
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