static bool
scsi_copy_dma_buffer(scsi_ccb *request, uint32 size, bool to_buffer)
{
dma_buffer *buffer = request->dma_buffer;
const physical_entry *sg_list = buffer->sg_list_orig;
uint32 num_vecs = buffer->sg_count_orig;
uchar *buffer_data = buffer->address;
SHOW_FLOW(1, "to_buffer=%d, %" B_PRIu32 " bytes", to_buffer, size);
// survive even if controller returned invalid data size
size = min_c(size, request->data_length);
// we have to use S/G list to original data; the DMA buffer
// was allocated in kernel and is thus visible even if the thread
// was changed
for (; size > 0 && num_vecs > 0; ++sg_list, --num_vecs) {
size_t bytes;
bytes = min_c( size, sg_list->size );
if (to_buffer) {
vm_memcpy_from_physical(buffer_data, sg_list->address, bytes,
false);
} else
vm_memcpy_to_physical(sg_list->address, buffer_data, bytes, false);
buffer_data += bytes;
}
return true;
}
/* static */ status_t
IORequest::_CopyPhysical(void* bounceBuffer, generic_addr_t external,
size_t size, team_id team, bool copyIn)
{
if (copyIn)
return vm_memcpy_from_physical(bounceBuffer, external, size, false);
return vm_memcpy_to_physical(external, bounceBuffer, size, false);
}
/* static */ status_t
IORequest::_CopyPhysical(void* bounceBuffer, void* external, size_t size,
team_id team, bool copyIn)
{
if (copyIn) {
return vm_memcpy_from_physical(bounceBuffer, (addr_t)external, size,
false);
}
return vm_memcpy_to_physical((addr_t)external, bounceBuffer, size, false);
}
/*! Copy data between request data and buffer
request - request to copy data from/to
offset - offset of data in request
allocation_length- limit of request's data buffer according to CDB
buffer - data to copy data from/to
size - number of bytes to copy
to_buffer - true: copy from request to buffer
false: copy from buffer to request
return: true, if data of request was large enough
*/
bool
copy_sg_data(scsi_ccb *request, uint offset, uint allocationLength,
void *buffer, int size, bool toBuffer)
{
const physical_entry *sgList = request->sg_list;
int sgCount = request->sg_count;
int requestSize;
SHOW_FLOW(3, "offset=%u, req_size_limit=%d, size=%d, sg_list=%p, sg_cnt=%d, %s buffer",
offset, allocationLength, size, sgList, sgCount, toBuffer ? "to" : "from");
// skip unused S/G entries
while (sgCount > 0 && offset >= sgList->size) {
offset -= sgList->size;
++sgList;
--sgCount;
}
if (sgCount == 0)
return 0;
// remaining bytes we are allowed to copy from/to request
requestSize = min_c(allocationLength, request->data_length) - offset;
// copy one S/G entry at a time
for (; size > 0 && requestSize > 0 && sgCount > 0; ++sgList, --sgCount) {
size_t bytes;
bytes = min_c(size, requestSize);
bytes = min_c(bytes, sgList->size);
SHOW_FLOW(4, "buffer=%p, virt_addr=%p, bytes=%d, to_buffer=%d",
buffer, (void *)(sgList->address + offset), (int)bytes, toBuffer);
if (toBuffer) {
vm_memcpy_from_physical(buffer, sgList->address + offset, bytes,
false);
} else {
vm_memcpy_to_physical(sgList->address + offset, buffer, bytes,
false);
}
buffer = (char *)buffer + bytes;
size -= bytes;
offset = 0;
}
return size == 0;
}
/*! Copy data between ccb data and buffer
ccb - ccb to copy data from/to
offset - offset of data in ccb
allocation_length- limit of ccb's data buffer according to CDB
buffer - data to copy data from/to
size - number of bytes to copy
to_buffer - true: copy from ccb to buffer
false: copy from buffer to ccb
return: true, if data of ccb was large enough
*/
bool
copy_sg_data(scsi_ccb *ccb, uint offset, uint allocationLength,
void *buffer, int size, bool toBuffer)
{
const physical_entry *sgList = ccb->sg_list;
int sgCount = ccb->sg_count;
// skip unused S/G entries
while (sgCount > 0 && offset >= sgList->size) {
offset -= sgList->size;
++sgList;
--sgCount;
}
if (sgCount == 0)
return false;
// remaining bytes we are allowed to copy from/to ccb
int requestSize = MIN(allocationLength, ccb->data_length) - offset;
// copy one S/G entry at a time
for (; size > 0 && requestSize > 0 && sgCount > 0; ++sgList, --sgCount) {
size_t bytes;
bytes = MIN(size, requestSize);
bytes = MIN(bytes, sgList->size);
if (toBuffer) {
vm_memcpy_from_physical(buffer, sgList->address + offset, bytes,
false);
} else {
vm_memcpy_to_physical(sgList->address + offset, buffer, bytes,
false);
}
buffer = (char *)buffer + bytes;
size -= bytes;
offset = 0;
}
return size == 0;
}
static status_t
cache_io(void* _cacheRef, void* cookie, off_t offset, addr_t buffer,
size_t* _size, bool doWrite)
{
if (_cacheRef == NULL)
panic("cache_io() called with NULL ref!\n");
file_cache_ref* ref = (file_cache_ref*)_cacheRef;
VMCache* cache = ref->cache;
off_t fileSize = cache->virtual_end;
bool useBuffer = buffer != 0;
TRACE(("cache_io(ref = %p, offset = %Ld, buffer = %p, size = %lu, %s)\n",
ref, offset, (void*)buffer, *_size, doWrite ? "write" : "read"));
// out of bounds access?
if (offset >= fileSize || offset < 0) {
*_size = 0;
return B_OK;
}
int32 pageOffset = offset & (B_PAGE_SIZE - 1);
size_t size = *_size;
offset -= pageOffset;
if ((off_t)(offset + pageOffset + size) > fileSize) {
// adapt size to be within the file's offsets
size = fileSize - pageOffset - offset;
*_size = size;
}
if (size == 0)
return B_OK;
// "offset" and "lastOffset" are always aligned to B_PAGE_SIZE,
// the "last*" variables always point to the end of the last
// satisfied request part
const uint32 kMaxChunkSize = MAX_IO_VECS * B_PAGE_SIZE;
size_t bytesLeft = size, lastLeft = size;
int32 lastPageOffset = pageOffset;
addr_t lastBuffer = buffer;
off_t lastOffset = offset;
size_t lastReservedPages = min_c(MAX_IO_VECS, (pageOffset + bytesLeft
+ B_PAGE_SIZE - 1) >> PAGE_SHIFT);
size_t reservePages = 0;
size_t pagesProcessed = 0;
cache_func function = NULL;
vm_page_reservation reservation;
reserve_pages(ref, &reservation, lastReservedPages, doWrite);
AutoLocker<VMCache> locker(cache);
while (bytesLeft > 0) {
// Periodically reevaluate the low memory situation and select the
// read/write hook accordingly
if (pagesProcessed % 32 == 0) {
if (size >= BYPASS_IO_SIZE
&& low_resource_state(B_KERNEL_RESOURCE_PAGES)
!= B_NO_LOW_RESOURCE) {
// In low memory situations we bypass the cache beyond a
// certain I/O size.
function = doWrite ? write_to_file : read_from_file;
} else
function = doWrite ? write_to_cache : read_into_cache;
}
// check if this page is already in memory
vm_page* page = cache->LookupPage(offset);
if (page != NULL) {
// The page may be busy - since we need to unlock the cache sometime
// in the near future, we need to satisfy the request of the pages
// we didn't get yet (to make sure no one else interferes in the
// meantime).
status_t status = satisfy_cache_io(ref, cookie, function, offset,
buffer, useBuffer, pageOffset, bytesLeft, reservePages,
lastOffset, lastBuffer, lastPageOffset, lastLeft,
lastReservedPages, &reservation);
if (status != B_OK)
return status;
// Since satisfy_cache_io() unlocks the cache, we need to look up
// the page again.
page = cache->LookupPage(offset);
if (page != NULL && page->busy) {
cache->WaitForPageEvents(page, PAGE_EVENT_NOT_BUSY, true);
continue;
}
}
size_t bytesInPage = min_c(size_t(B_PAGE_SIZE - pageOffset), bytesLeft);
TRACE(("lookup page from offset %Ld: %p, size = %lu, pageOffset "
"= %lu\n", offset, page, bytesLeft, pageOffset));
if (page != NULL) {
if (doWrite || useBuffer) {
// Since the following user_mem{cpy,set}() might cause a page
// fault, which in turn might cause pages to be reserved, we
// need to unlock the cache temporarily to avoid a potential
// deadlock. To make sure that our page doesn't go away, we mark
// it busy for the time.
page->busy = true;
locker.Unlock();
// copy the contents of the page already in memory
phys_addr_t pageAddress
= (phys_addr_t)page->physical_page_number * B_PAGE_SIZE
+ pageOffset;
bool userBuffer = IS_USER_ADDRESS(buffer);
if (doWrite) {
if (useBuffer) {
vm_memcpy_to_physical(pageAddress, (void*)buffer,
bytesInPage, userBuffer);
} else {
vm_memset_physical(pageAddress, 0, bytesInPage);
}
} else if (useBuffer) {
vm_memcpy_from_physical((void*)buffer, pageAddress,
bytesInPage, userBuffer);
}
locker.Lock();
if (doWrite) {
DEBUG_PAGE_ACCESS_START(page);
page->modified = true;
if (page->State() != PAGE_STATE_MODIFIED)
vm_page_set_state(page, PAGE_STATE_MODIFIED);
DEBUG_PAGE_ACCESS_END(page);
}
cache->MarkPageUnbusy(page);
}
// If it is cached only, requeue the page, so the respective queue
// roughly remains LRU first sorted.
if (page->State() == PAGE_STATE_CACHED
|| page->State() == PAGE_STATE_MODIFIED) {
DEBUG_PAGE_ACCESS_START(page);
vm_page_requeue(page, true);
DEBUG_PAGE_ACCESS_END(page);
}
if (bytesLeft <= bytesInPage) {
// we've read the last page, so we're done!
locker.Unlock();
vm_page_unreserve_pages(&reservation);
return B_OK;
}
// prepare a potential gap request
lastBuffer = buffer + bytesInPage;
lastLeft = bytesLeft - bytesInPage;
lastOffset = offset + B_PAGE_SIZE;
lastPageOffset = 0;
}
if (bytesLeft <= bytesInPage)
break;
buffer += bytesInPage;
bytesLeft -= bytesInPage;
pageOffset = 0;
offset += B_PAGE_SIZE;
pagesProcessed++;
if (buffer - lastBuffer + lastPageOffset >= kMaxChunkSize) {
status_t status = satisfy_cache_io(ref, cookie, function, offset,
buffer, useBuffer, pageOffset, bytesLeft, reservePages,
lastOffset, lastBuffer, lastPageOffset, lastLeft,
lastReservedPages, &reservation);
if (status != B_OK)
return status;
}
}
// fill the last remaining bytes of the request (either write or read)
return function(ref, cookie, lastOffset, lastPageOffset, lastBuffer,
lastLeft, useBuffer, &reservation, 0);
}
/*! Like read_into_cache() but writes data into the cache.
To preserve data consistency, it might also read pages into the cache,
though, if only a partial page gets written.
The same restrictions apply.
*/
static status_t
write_to_cache(file_cache_ref* ref, void* cookie, off_t offset,
int32 pageOffset, addr_t buffer, size_t bufferSize, bool useBuffer,
vm_page_reservation* reservation, size_t reservePages)
{
// TODO: We're using way too much stack! Rather allocate a sufficiently
// large chunk on the heap.
generic_io_vec vecs[MAX_IO_VECS];
uint32 vecCount = 0;
generic_size_t numBytes = PAGE_ALIGN(pageOffset + bufferSize);
vm_page* pages[MAX_IO_VECS];
int32 pageIndex = 0;
status_t status = B_OK;
// ToDo: this should be settable somewhere
bool writeThrough = false;
// allocate pages for the cache and mark them busy
for (generic_size_t pos = 0; pos < numBytes; pos += B_PAGE_SIZE) {
// TODO: if space is becoming tight, and this cache is already grown
// big - shouldn't we better steal the pages directly in that case?
// (a working set like approach for the file cache)
// TODO: the pages we allocate here should have been reserved upfront
// in cache_io()
vm_page* page = pages[pageIndex++] = vm_page_allocate_page(
reservation,
(writeThrough ? PAGE_STATE_CACHED : PAGE_STATE_MODIFIED)
| VM_PAGE_ALLOC_BUSY);
page->modified = !writeThrough;
ref->cache->InsertPage(page, offset + pos);
add_to_iovec(vecs, vecCount, MAX_IO_VECS,
page->physical_page_number * B_PAGE_SIZE, B_PAGE_SIZE);
}
push_access(ref, offset, bufferSize, true);
ref->cache->Unlock();
vm_page_unreserve_pages(reservation);
// copy contents (and read in partially written pages first)
if (pageOffset != 0) {
// This is only a partial write, so we have to read the rest of the page
// from the file to have consistent data in the cache
generic_io_vec readVec = { vecs[0].base, B_PAGE_SIZE };
generic_size_t bytesRead = B_PAGE_SIZE;
status = vfs_read_pages(ref->vnode, cookie, offset, &readVec, 1,
B_PHYSICAL_IO_REQUEST, &bytesRead);
// ToDo: handle errors for real!
if (status < B_OK)
panic("1. vfs_read_pages() failed: %s!\n", strerror(status));
}
size_t lastPageOffset = (pageOffset + bufferSize) % B_PAGE_SIZE;
if (lastPageOffset != 0) {
// get the last page in the I/O vectors
generic_addr_t last = vecs[vecCount - 1].base
+ vecs[vecCount - 1].length - B_PAGE_SIZE;
if ((off_t)(offset + pageOffset + bufferSize) == ref->cache->virtual_end) {
// the space in the page after this write action needs to be cleaned
vm_memset_physical(last + lastPageOffset, 0,
B_PAGE_SIZE - lastPageOffset);
} else {
// the end of this write does not happen on a page boundary, so we
// need to fetch the last page before we can update it
generic_io_vec readVec = { last, B_PAGE_SIZE };
generic_size_t bytesRead = B_PAGE_SIZE;
status = vfs_read_pages(ref->vnode, cookie,
PAGE_ALIGN(offset + pageOffset + bufferSize) - B_PAGE_SIZE,
&readVec, 1, B_PHYSICAL_IO_REQUEST, &bytesRead);
// ToDo: handle errors for real!
if (status < B_OK)
panic("vfs_read_pages() failed: %s!\n", strerror(status));
if (bytesRead < B_PAGE_SIZE) {
// the space beyond the file size needs to be cleaned
vm_memset_physical(last + bytesRead, 0,
B_PAGE_SIZE - bytesRead);
}
}
}
for (uint32 i = 0; i < vecCount; i++) {
generic_addr_t base = vecs[i].base;
generic_size_t bytes = min_c((generic_size_t)bufferSize,
generic_size_t(vecs[i].length - pageOffset));
if (useBuffer) {
// copy data from user buffer
vm_memcpy_to_physical(base + pageOffset, (void*)buffer, bytes,
IS_USER_ADDRESS(buffer));
} else {
// clear buffer instead
vm_memset_physical(base + pageOffset, 0, bytes);
}
bufferSize -= bytes;
if (bufferSize == 0)
break;
buffer += bytes;
pageOffset = 0;
}
if (writeThrough) {
// write cached pages back to the file if we were asked to do that
status_t status = vfs_write_pages(ref->vnode, cookie, offset, vecs,
vecCount, B_PHYSICAL_IO_REQUEST, &numBytes);
if (status < B_OK) {
// ToDo: remove allocated pages, ...?
panic("file_cache: remove allocated pages! write pages failed: %s\n",
strerror(status));
}
}
if (status == B_OK)
reserve_pages(ref, reservation, reservePages, true);
ref->cache->Lock();
// make the pages accessible in the cache
for (int32 i = pageIndex; i-- > 0;) {
ref->cache->MarkPageUnbusy(pages[i]);
DEBUG_PAGE_ACCESS_END(pages[i]);
}
return status;
}
