Commit 82bb12f0 authored by David Brownell's avatar David Brownell Committed by Greg Kroah-Hartman

[PATCH] ohci uses less slab memory

When chasing down some of those 'bad entry' diagnostics, I once
got suspicious that the problem was slab corruption coming from
the way the td hashtable code worked.   So I put together this
patch, eliminating some kmallocation, and the next times I ran
that test, the oops went away and it worked like a charm.  Hmm.

This patch is good because it shrinks memory and code, and gets
rid of some could-fail allocations, so I figured I'd send it on
(low priority) even if I don't think it fixes the root problem.
parent eba7db30
...@@ -14,7 +14,8 @@ ...@@ -14,7 +14,8 @@
* - data used only by the HCD ... kmalloc is fine * - data used only by the HCD ... kmalloc is fine
* - async and periodic schedules, shared by HC and HCD ... these * - async and periodic schedules, shared by HC and HCD ... these
* need to use pci_pool or pci_alloc_consistent * need to use pci_pool or pci_alloc_consistent
* - driver buffers, read/written by HC ... single shot DMA mapped * - driver buffers, read/written by HC ... the hcd glue or the
* device driver provides us with dma addresses
* *
* There's also PCI "register" data, which is memory mapped. * There's also PCI "register" data, which is memory mapped.
* No memory seen by this driver is pagable. * No memory seen by this driver is pagable.
...@@ -41,95 +42,6 @@ static void ohci_hcd_free (struct usb_hcd *hcd) ...@@ -41,95 +42,6 @@ static void ohci_hcd_free (struct usb_hcd *hcd)
/*-------------------------------------------------------------------------*/ /*-------------------------------------------------------------------------*/
/* Recover a TD/ED using its collision chain */
static inline void *
dma_to_ed_td (struct hash_list_t * entry, dma_addr_t dma)
{
struct hash_t * scan = entry->head;
while (scan && scan->dma != dma)
scan = scan->next;
return scan ? scan->virt : 0;
}
static inline struct td *
dma_to_td (struct ohci_hcd *hc, dma_addr_t td_dma)
{
td_dma &= TD_MASK;
return (struct td *) dma_to_ed_td(&(hc->td_hash [TD_HASH_FUNC(td_dma)]),
td_dma);
}
// FIXME: when updating the hashtables this way, mem_flags is unusable...
/* Add a hash entry for a TD/ED; return true on success */
static inline int
hash_add_ed_td (
struct hash_list_t *entry,
void *virt,
dma_addr_t dma,
int mem_flags
)
{
struct hash_t * scan;
scan = (struct hash_t *) kmalloc (sizeof *scan, mem_flags);
if (!scan)
return 0;
if (!entry->tail) {
entry->head = entry->tail = scan;
} else {
entry->tail->next = scan;
entry->tail = scan;
}
scan->virt = virt;
scan->dma = dma;
scan->next = NULL;
return 1;
}
static inline int
hash_add_td (struct ohci_hcd *hc, struct td *td, int mem_flags)
{
return hash_add_ed_td (&(hc->td_hash [TD_HASH_FUNC (td->td_dma)]),
td, td->td_dma, mem_flags);
}
static inline void
hash_free_ed_td (struct hash_list_t *entry, void *virt)
{
struct hash_t *scan, *prev;
scan = prev = entry->head;
// Find and unlink hash entry
while (scan && scan->virt != virt) {
prev = scan;
scan = scan->next;
}
if (scan) {
if (scan == entry->head) {
if (entry->head == entry->tail)
entry->head = entry->tail = NULL;
else
entry->head = scan->next;
} else if (scan == entry->tail) {
entry->tail = prev;
prev->next = NULL;
} else
prev->next = scan->next;
kfree(scan);
}
}
static inline void
hash_free_td (struct ohci_hcd *hc, struct td * td)
{
hash_free_ed_td (&(hc->td_hash[TD_HASH_FUNC(td->td_dma)]), td);
}
static int ohci_mem_init (struct ohci_hcd *ohci) static int ohci_mem_init (struct ohci_hcd *ohci)
{ {
ohci->td_cache = pci_pool_create ("ohci_td", ohci->hcd.pdev, ohci->td_cache = pci_pool_create ("ohci_td", ohci->hcd.pdev,
...@@ -161,6 +73,21 @@ static void ohci_mem_cleanup (struct ohci_hcd *ohci) ...@@ -161,6 +73,21 @@ static void ohci_mem_cleanup (struct ohci_hcd *ohci)
} }
} }
/*-------------------------------------------------------------------------*/
/* ohci "done list" processing needs this mapping */
static inline struct td *
dma_to_td (struct ohci_hcd *hc, dma_addr_t td_dma)
{
struct td *td;
td_dma &= TD_MASK;
td = hc->td_hash [TD_HASH_FUNC(td_dma)];
while (td && td->td_dma != td_dma)
td = td->td_hash;
return td;
}
/* TDs ... */ /* TDs ... */
static struct td * static struct td *
td_alloc (struct ohci_hcd *hc, int mem_flags) td_alloc (struct ohci_hcd *hc, int mem_flags)
...@@ -170,12 +97,17 @@ td_alloc (struct ohci_hcd *hc, int mem_flags) ...@@ -170,12 +97,17 @@ td_alloc (struct ohci_hcd *hc, int mem_flags)
td = pci_pool_alloc (hc->td_cache, mem_flags, &dma); td = pci_pool_alloc (hc->td_cache, mem_flags, &dma);
if (td) { if (td) {
int hash;
/* in case hc fetches it, make it look dead */
memset (td, 0, sizeof *td);
td->hwNextTD = cpu_to_le32 (dma);
td->td_dma = dma; td->td_dma = dma;
/* hash it for later reverse mapping */ /* hash it for later reverse mapping */
if (!hash_add_td (hc, td, mem_flags)) { hash = TD_HASH_FUNC (dma);
pci_pool_free (hc->td_cache, td, dma); td->td_hash = hc->td_hash [hash];
return NULL; hc->td_hash [hash] = td;
}
} }
return td; return td;
} }
...@@ -183,10 +115,18 @@ td_alloc (struct ohci_hcd *hc, int mem_flags) ...@@ -183,10 +115,18 @@ td_alloc (struct ohci_hcd *hc, int mem_flags)
static void static void
td_free (struct ohci_hcd *hc, struct td *td) td_free (struct ohci_hcd *hc, struct td *td)
{ {
hash_free_td (hc, td); struct td **prev = &hc->td_hash [TD_HASH_FUNC (td->td_dma)];
while (*prev && *prev != td)
prev = &(*prev)->td_hash;
if (*prev)
*prev = td->td_hash;
else
dev_dbg (*hc->hcd.controller, "bad hash for td %p\n", td);
pci_pool_free (hc->td_cache, td, td->td_dma); pci_pool_free (hc->td_cache, td, td->td_dma);
} }
/*-------------------------------------------------------------------------*/
/* EDs ... */ /* EDs ... */
static struct ed * static struct ed *
......
...@@ -111,6 +111,7 @@ struct td { ...@@ -111,6 +111,7 @@ struct td {
/* rest are purely for the driver's use */ /* rest are purely for the driver's use */
__u8 index; __u8 index;
struct ed *ed; struct ed *ed;
struct td *td_hash; /* dma-->td hashtable */
struct td *next_dl_td; struct td *next_dl_td;
struct urb *urb; struct urb *urb;
...@@ -320,23 +321,9 @@ typedef struct urb_priv { ...@@ -320,23 +321,9 @@ typedef struct urb_priv {
#define URB_DEL 1 #define URB_DEL 1
/* Hash struct used for TD/ED hashing */
struct hash_t {
void *virt;
dma_addr_t dma;
struct hash_t *next; // chaining for collision cases
};
/* List of TD/ED hash entries */
struct hash_list_t {
struct hash_t *head;
struct hash_t *tail;
};
#define TD_HASH_SIZE 64 /* power'o'two */ #define TD_HASH_SIZE 64 /* power'o'two */
// sizeof (struct td) ~= 64 == 2^6 ...
#define TD_HASH_FUNC(td_dma) ((td_dma ^ (td_dma >> 5)) % TD_HASH_SIZE) #define TD_HASH_FUNC(td_dma) ((td_dma ^ (td_dma >> 6)) % TD_HASH_SIZE)
/* /*
...@@ -373,7 +360,7 @@ struct ohci_hcd { ...@@ -373,7 +360,7 @@ struct ohci_hcd {
*/ */
struct pci_pool *td_cache; struct pci_pool *td_cache;
struct pci_pool *ed_cache; struct pci_pool *ed_cache;
struct hash_list_t td_hash [TD_HASH_SIZE]; struct td *td_hash [TD_HASH_SIZE];
/* /*
* driver state * driver state
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment