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1194b5ce57
Unlike the legacy I/O path, scsi-mq preallocates a large array to hold the scatterlist for each request. This static allocation can consume substantial amounts of memory on modern controllers which support a large number of concurrently outstanding requests. To facilitate a switch to a smaller static allocation combined with a dynamic allocation for requests that need it, we need to make sure all SCSI drivers handle chained scatterlists correctly. Convert remaining drivers that directly dereference the scatterlist array to using the iterator functions. [mkp: clarified commit message] Cc: Oliver Neukum <oliver@neukum.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-usb@vger.kernel.org Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
56 lines
1.0 KiB
C
56 lines
1.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Driver for Microtek Scanmaker X6 USB scanner and possibly others.
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*
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* (C) Copyright 2000 John Fremlin <vii@penguinpowered.com>
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* (C) Copyright 2000 Oliver Neukum <Oliver.Neukum@lrz.uni-muenchen.de>
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*
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* See microtek.c for history
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*
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*/
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typedef void (*mts_scsi_cmnd_callback)(struct scsi_cmnd *);
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struct mts_transfer_context
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{
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struct mts_desc *instance;
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mts_scsi_cmnd_callback final_callback;
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struct scsi_cmnd *srb;
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void *data;
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unsigned data_length;
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int data_pipe;
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struct scatterlist *curr_sg;
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u8 *scsi_status; /* status returned from ep_response after command completion */
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};
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struct mts_desc {
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struct mts_desc *next;
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struct mts_desc *prev;
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struct usb_device *usb_dev;
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struct usb_interface *usb_intf;
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/* Endpoint addresses */
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u8 ep_out;
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u8 ep_response;
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u8 ep_image;
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struct Scsi_Host *host;
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struct urb *urb;
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struct mts_transfer_context context;
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};
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#define MTS_EP_OUT 0x1
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#define MTS_EP_RESPONSE 0x2
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#define MTS_EP_IMAGE 0x3
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#define MTS_EP_TOTAL 0x3
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#define MTS_SCSI_ERR_MASK ~0x3fu
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